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by Matthew Palmer

Unlike most countries’ constitutions, New Zealand’s is not contained in one document, but is made up a variety of laws, legal judgments and conventions. This means the country’s constitution can be changed comparatively easily, but that flexibility gives New Zealand’s Parliament more power than those in other Westminster systems.

What is a constitution?

The constitution of a nation is the set of rules that govern how a government can exercise public power. A constitution identifies who or what institutions should exercise power and how they should do it. The government is usually the most powerful coercive force within a country, so the rules about how a government should exercise power are very important.


In a democracy the purpose of a constitution is to prevent the government from abusing its power over the people of a nation, and to ensure that the government exercises its power as the people wish. It can be complicated to create, as people will disagree over how a government should exercise its power.

Australian Kiwis?

The Australian constitution is contained in the Commonwealth of Australia Constitution Act 1900. The act was passed by the UK Parliament after two conventions and referendums in the colonies of Queensland, New South Wales, Victoria, Tasmania, South Australia, and Western Australia. New Zealand decided not to join the Commonwealth of Australia, but this is still possible if it wants to do so.

Written or unwritten?

In most countries the constitution is a written document. The USA, Australia, Canada, China, India and almost every other nation have a single written document. A written constitution usually provides for the basic institutions that exercise public power, and how they do it. It also usually provides procedures for how the constitutional rules are enforced and how they may be changed.

Unlike most countries, New Zealand follows the UK in considering itself to have an ‘unwritten’ constitution. New Zealand has had a succession of constitution acts, passed first by the UK Parliament in 1846 (but then suspended) and 1852, and then by the New Zealand Parliament in 1986. These acts have contained key provisions relating to the institutions and procedures of government.

The Constitution Act 1986 brought together key legal provisions regarding the institutions and procedures for the exercise of power that had previously been scattered in several places. It was organised in four main parts, dealing with:

  • the sovereign – the king or queen and their representative in New Zealand, the governor-general
  • the executive – government ministers
  • the legislature – the House of Representatives which, together with the sovereign, is Parliament
  • the judiciary – judges.

Canada, Australia and other former British colonies have also had constitution acts, initially passed by the UK Parliament, which have been referred to as ‘the constitution’ in those nations. But, since around 1860, New Zealand has not considered one act to be its constitution.

Outside the US Constitution

One of the most distinctive constitutional characteristics of the USA is that the Supreme Court can strike down legislation passed by Congress if it is inconsistent with the US Constitution. However, most Americans do not realise that this is not provided for in the written US Constitution itself. Rather, it was devised by the Supreme Court in its judgment in the case Marbury v Madison in 1803.

Why unwritten?

It is not clear why New Zealand’s constitution is regarded as unwritten. Key institutions and rules governing the exercise of public power in Australia, Canada and the USA are also based on practice or convention outside written provisions of their constitutions. But those nations still consider their constitution to be in one written document.

Perhaps aspects of New Zealand’s constitutional history have led to a greater focus on the importance of constitutional conventions rather than written documents. Possibly New Zealand’s ability to amend the Constitution Act itself from 1857 lessened its apparent significance. Or perhaps it is significant that New Zealand’s Constitution Act 1986 is not supreme law: the New Zealand judiciary does not have the role or power to strike down other laws as inconsistent with the act.

Whatever the reasons, like the UK, New Zealand considers that its basic institutions and procedures governing the exercise of public power – its constitution – are set out in both written documents and unwritten practices.

Fitzgerald v Muldoon

A month after winning the 1975 general election, Prime Minister Robert Muldoon issued a press statement saying that compulsory superannuation contributions no longer needed to be made. After a public servant (a Mr Fitzgerald) took Muldoon to court, Chief Justice Richard Wild declared that the prime minister’s statement breached article 1 of the Bill of Rights 1688, which prohibited the suspension of the law by regal authority. However, recognising that Parliament would pass the necessary legislation, the chief justice adjourned the case for six months to allow that to occur.

Sources of New Zealand’s constitution

New Zealand’s constitution is located in a variety of laws, court judgments, other instruments of government and constitutional conventions. Different scholars and commentators identify and emphasise different elements of the constitution. But there is general consensus that New Zealand’s constitution includes:

  • statutes passed in the UK before New Zealand was independent, such as the Magna Carta, which was confirmed as statute law in 1297, the Bill of Rights Act 1688 and the New Zealand Constitution Act 1852
  • statutes passed by the New Zealand Parliament, such as the Constitution Act 1986 and the Electoral Act 1993
  • significant court judgments, such as Fitzgerald v Muldoon (1976), which declared that the prime minister could not suspend the law
  • elements of other instruments of New Zealand branches of government, such as the letters patent (legal documents issued by heads of states or governments which confer rights and privileges) and the Cabinet manual
  • constitutional conventions.

Many commentators consider the Treaty of Waitangi to be part of New Zealand’s constitutional arrangements, but the position of the treaty is disputed.

Constitutional conventions


Constitutional conventions are the most unwritten part of the New Zealand constitution. They are practices of constitutional behaviour that have been followed so consistently and which are believed to have such force that they are generally considered to govern constitutional behaviour.

Canadian constitutional conventions

The Canadian Supreme Court has pointed out that constitutional conventions may be more important than some laws and summarised the situation in an equation: ‘constitutional conventions plus constitutional law equal the total constitution of the country.’1

Conventions may not be enforced by the courts. They live and die according to continued practice and belief.

Examples of constitutional conventions

Constitutional conventions provide some of the key rules of New Zealand’s constitution. They add to, or take away from, legal rules in sometimes dramatic ways. Examples include:

  • the convention of individual ministerial responsibility, which gives individual ministers the responsibility to answer to the House of Representatives for the exercise of their powers, including their powers to direct the public service within their portfolio and within the law
  • the convention of collective cabinet responsibility, which gives cabinet collectively the power to direct individual ministers, since all ministers have to publicly support the decisions of cabinet
  • the convention of collective cabinet responsibility is also significant for the stability of a government – if the House of Representatives passes a motion of no confidence in the government, the government falls and becomes a caretaker government until a new government can be formed with the confidence of the house
  • the convention of caretaker government, which provides that a government must significantly constrain its decision-making if it loses the confidence of the House of Representatives, even while having full legal powers to govern
  • the convention that the sovereign only acts on the advice of ministers subordinates the monarch’s legal powers (and those of his or her representative in New Zealand, the governor-general) to cabinet.

Executive and legislature

The sovereign

The sovereign monarch is the head of state of New Zealand. She or he is represented in New Zealand by the governor-general, who is appointed on the advice of the prime minister. The sovereign, or the governor-general, exercises almost all their powers on the basis of advice from the prime minister and the other ministers, who must be members of Parliament.


A government must have the confidence of a majority of the members of the House of Representatives in order to advise the governor-general and sovereign. If a government loses that confidence, it must operate as a ‘caretaker government’ until a new government is formed. A caretaker government should avoid taking significant actions or making policy decisions which will have a long-term effect.

Elections must be held at least every three years and ‘snap elections’ (elections called earlier than expected) may be called. Since 1996 elections have been run on the basis of the mixed-member proportional (MMP) electoral system.

Official information is available to the public unless there is good reason why it should be withheld. This regime is policed by the ombudsman. The news media and commentators on the internet are able to disseminate and analyse news of political events, and policy and legal issues.

Entrenched provisions

Six provisions in New Zealand law are constitutionally entrenched, meaning they can only be changed by a vote of more than 75% of the House of Representatives or more than 50% of voters at a referendum. They are contained in the Electoral Act 1993 (and one in the Constitution Act 1986) and relate to:

  • the term of Parliament
  • the Representation Commission (a committee that determines electoral boundaries)
  • the division of New Zealand into general electorates
  • the 5% margin for the population of general electorates
  • the minimum voting age of 18
  • the method of secret voting.

Electoral seats

The Electoral Act 1993 entrenches provisions of New Zealand law. The division of New Zealand into general electorates is entrenched but the Māori electorates are not. Entrenching the Māori seats was a policy of the Māori Party (Te Pāti Māori) in the early 21st century.


Parliament consists of the House of Representatives and the sovereign. Parliament has the supreme power to make or unmake law, including:

  • primary legislation and regulations
  • legislation that turns international obligations into New Zealand law
  • appropriations (parliamentary votes of money) that authorise expenditure, taxation or borrowing.

Parliament also makes and unmakes governments.

The House of Representatives has control of, and enforces, its own procedures, though in so doing it should observe the rights and freedoms in the New Zealand Bill of Rights Act 1990. The attorney-general (a minister) must draw the attention of the House of Representatives to provisions of draft legislation that may unjustifiably override those rights and freedoms.

The remuneration (pay) of members of Parliament is determined independently by the Remuneration Authority.

The executive

The executive branch of government ‘executes’ laws and policies. It is headed by cabinet, which collectively directs the powers of individual ministers to instruct politically neutral public servants. Cabinet directs the armed forces and police, except in relation to specific operational matters, and conducts foreign relations, including having the power to enter into international obligations. The solicitor-general (an official) supervises indictable (serious) prosecutions.

The government’s powers are limited only by the need to retain the confidence of the House of Representatives and the need to act within the law, including the law with regard to parliamentary appropriations of public money for expenditure.

The government is the primary initiator of proposals to Parliament for public expenditure or for changes to the law.

Judicial limits on the executive

The judiciary

The judiciary is independent of the executive and Parliament. Judges are appointed by the executive, from the ranks of experienced lawyers, on a non-political basis. Judges may be removed by a parliamentary procedure initiated by the attorney-general which is difficult to invoke. Their pay is determined independently by the Remuneration Authority.

Judging the judges

The Office of the Judicial Conduct Commissioner, established in 2005, deals with complaints about the conduct of judges. It cannot investigate complaints about judges’ decisions. In 2009/10, of the 148 complaints investigated (an additional 138 complaints had not been fully investigated by the end of the financial year), 125 were dismissed. The most common ground for dismissal was that the complaint was about the judge’s decision. Only 7 of the 148 complaints were referred for further investigation.

The judiciary, organised in a hierarchy of courts, makes decisions on court cases and has input into the executive government’s management of the court system. High Court judges have both statutory jurisdiction (the authority to make rulings on legal matters governed by legislation) and inherent common law jurisdiction (the power to act as they see fit – but not contrary to law – to deal with issues before the court). Court procedures are formulated by the judiciary, and by the Rules Committee (a statutory body made up of judges, lawyers, the solicitor-general, the attorney-general and the chief executive of the Ministry of Justice) with the consent of cabinet.

The judiciary makes common law by making individual legal decisions, and giving reasons for these decisions. The judiciary interprets legislation using techniques they have developed as well as techniques set out by Parliament.

Protections for citizens

If the government infringes the civil and political rights and freedoms in the New Zealand Bill of Rights Act 1990, it can be sued in court. A court may order the government to pay money in damages for infringements. If government infringement is clearly authorised by legislation, the judiciary may not strike down the validity of that infringement – but they may declare that it exists.

Both the government and the private sector are prohibited from discriminating on specified grounds of human rights in particular areas of activity. Complaints about the operation of government may be made to Parliament and a variety of complaints agencies, such as the ombudsmen, the privacy commissioner, the Human Rights Commission and the Independent Police Conduct Authority.

Limits of national government

Local government is created by laws passed by Parliament. Local government, on a municipal (towns and cities) and regional level, can make its own regulations, especially in relation to environmental matters.

The New Zealand government regards itself as bound by the international obligations it enters into. International obligations can only be enforced in a New Zealand court if a New Zealand act of Parliament has been passed saying that it can be. New Zealand is also bound by, and participates in, the United Nations and the World Trade Organization. New Zealand is subject to decisions by international judicial bodies such as the International Court of Justice and the International Criminal Court.

Constitutional change

Every constitution changes over time, and New Zealand’s constitution changes constantly – whenever there are changes in the laws, court judgments, instruments of government and constitutional conventions that make up its unwritten constitution.

Easy change

In 2005 the government moved three versions of a supplementary order paper to change the Constitution Act 1986 in two ways. The changes were relatively technical and were supported by all political parties. Despite their significance, they received only six submissions from the public, which took 20 minutes to hear. They were the subject of little debate and went largely unnoticed.

Statute changes

Other than the entrenched provisions, constitutional statutes can be changed by a simple majority vote in the House of Representatives. Sometimes these changes are large and noticeable, such as the enactment of the system of mixed-member proportional (MMP) electoral system in the Electoral Act 1993, which followed two referendums, and the enactment of the New Zealand Bill of Rights Act 1990 after four years of debate. Some are controversial, such as abolishing New Zealanders’ right to appeal to the Judicial Committee of the Privy Council in the United Kingdom by the Supreme Court Act 2003.

Agreeing to disagree

The constitutional convention that ministers may not publicly disagree with cabinet decisions is what gives cabinet its power. From 1999 coalition governments adopted ‘agree to disagree’ procedures to manage significant differences between coalition partners. Since 2005 there has been an additional innovation that a minor coalition party could be bound by cabinet unanimity in respect of some cabinet decisions, relating to the portfolios its own members held as ministers, but not in relation to other cabinet decisions.

Some changes to New Zealand’s constitutional statutes happen quickly. The Constitution Act 1986 was passed through its second reading, committee stages and third reading in a single evening in December 1986.

Less visible changes

Changes to instruments of government such as the Cabinet manual or Parliament’s standing orders are generally easier to implement and happen less publicly than changes to statutes.

Changes to constitutional conventions can be hard to notice. A change to a convention occurs simply with a change in practice. But it has to be a change in practice that is accepted and sustained over a lengthy period to qualify as a change in convention.

Pragmatic evolution

In a 2005 report, the Constitutional Arrangements Committee of the House of Representatives said: ‘Although the characterisation of New Zealand’s constitutional history did not come easily to us, we rapidly agreed on the characteristic qualities of New Zealand’s approach to constitutional change through its modern history. We adopted the tag of “pragmatic evolution”. By this we mean New Zealanders’ instinct to fix things when they need fixing, when they can fix them, without necessarily relating them to any grand philosophical scheme.’1

Flexible constitution

How easily a nation’s constitution may change is important. It determines how easy it is to change the rules that govern the exercise of public power – for the better or for the worse.

New Zealand’s constitution is easy to change compared to other nations. That means that it is flexible and can adapt to changing circumstances quickly and easily. It also means that people may not notice when the constitution changes – in this sense, New Zealand’s constitution is relatively vulnerable to changes that allow the abuse of public power. New Zealanders have varied views on the trade-off between flexibility and vulnerability in their constitution.


Constitutional relationships between the Crown and Māori

Key documents

The relationships between the Crown and Māori in New Zealand have been uneasy since first contact. In 1835, 34 northern chiefs, encouraged by official British Resident James Busby, signed the Declaration of Independence, a document which asserted their rangatiratanga (sovereignty).

In 1840, British Consul William Hobson oversaw the drafting of te Tiriti o Waitangi (the Treaty of Waitangi) in English and Māori. More than 500 chiefs signed the treaty during the course of the year, but some refused to sign.

In May 1840, the British Crown asserted that it had sovereignty over New Zealand. It is that assertion that is important legally, rather than the treaty itself, which was the moral or political justification used by the Crown for its assertion.

High stakes

In 1839 prospective New Zealand Company settlers drew up a constitution in England before leaving for Port Nicholson (Wellington). After arriving in early 1840 they arranged a meeting with Māori chiefs in order to ratify and confirm the constitution. William Hobson saw this as a treasonous act and it prompted his assertion of the British Crown’s sovereignty over the whole of New Zealand on the basis of the Treaty of Waitangi.

Versions of the Treaty of Waitangi

The English version of the Treaty of Waitangi guaranteed to Māori the full, exclusive and undisturbed possession of their lands, forests, fisheries and other properties, in exchange for ceding their sovereignty to the Crown.

The Māori version of the treaty, which was the version most Māori signed, preserved to Māori their rangatiratanga (literally ‘chieftainship’) over their lands, villages and all their taonga (treasures), in exchange for their gift to the Crown of their kāwanatanga (literally, ‘governorship’). In both versions the Crown guaranteed Māori its protection and conferred upon them the rights and privileges, or tikanga, of British subjects.


The Treaty of Waitangi represented an agreement between the Crown and many Māori chiefs to share power in some way. But exactly how was probably unclear in 1840, and remained unclear. As increasing numbers of settlers came to New Zealand, and promises in either version of the treaty went unfulfilled, conflict was inevitable. Fighting ensued, especially in the 1860s. The overall result was that the Crown’s sovereignty was confirmed, though in some areas of New Zealand that was as late as the 1880s and probably, in Te Urewera, the 1920s. It was also resented by many Māori.

Legal recognition

Until the end of the 20th century, the Treaty of Waitangi was virtually invisible to New Zealand law. However, its meaning and significance were reinterpreted by official institutions between 1973 and 1993. Parliament created the Waitangi Tribunal in 1975 and gave it the task of resolving the meaning of the treaty, treating each language version as of equal status. The Waitangi Tribunal issued four reports – from 1983 to 1986 – offering a general meaning of the treaty based on relationships and procedural fairness.

Parliament referred to the treaty in legislation from 1986. The courts adopted the tribunal’s meaning in a series of cases from 1987 to 1993. The executive government went along with that meaning.

General meaning of the treaty

The Treaty of Waitangi today occupies an uneasy, uncertain, place in New Zealand’s constitution. Its general meaning is commonly interpreted by official institutions and the law as being about relationships and procedural fairness. Despite these general principles, its meaning in particular cases can be unclear, and it is also unclear which institutions have the job of providing clarity.

Representative democracy and Parliament

Colonial developments

New Zealand became a British colony in the wake of the UK’s Reform Act 1832 – a big step towards democracy in Britain – and successor acts in 1835 and 1836. The settlements established by the New Zealand Company between 1840 and 1850 were loud in their demands for democratic representation. The first New Zealand Constitution Act was passed in 1846, partly in response to the settlers’ demands for representation. The act was suspended in 1848, partly because of concerns about representation, including the lack of Māori representation.

The first parliamentary election was held in 1853, and Parliament first sat in 1854. Its first two years of life were dominated by politicians’ ultimately successful demand that the governor be advised by ministers responsible to, and with the confidence of, the House of Representatives. The first significant exercise of Parliament’s power – to amend its own Constitution Act, in 1858 – related to electoral legislation.


The importance of voting continued to be emphasised in 19th-century New Zealand by the:

  • extension of voting to holders of miner’s rights (licences) in 1860
  • extension of voting to Māori men over 21 in 1867
  • extension of voting to all males over 21 in 1879
  • abolition of plural voting (where a person could vote in all electorates in which they owned or leased property) in 1889
  • extension of voting to all adult women in 1893 – New Zealand was the first country in the world to do this.

Proportional representation

The most significant constitutional change in 20th-century New Zealand was the introduction of proportional representation – the mixed-member proportional (MMP) system in 1996. This changed constitutional dynamics by requiring political parties to negotiate with each other to form a government and to pass legislation, as it became very difficult for one party to gain a majority of seats in Parliament.

Parliament rules

Continuing reliance on representative democracy has gone hand in hand with faith in the power of an elected Parliament to rule New Zealand.

Parliament has consistently asserted its power against other contenders, such as:

  • the UK, with New Zealand’s acquisition of the power to amend its own constitution in 1857, its rejection of joining Australia in 1900, acquisition of dominion status in 1907 and the Statute of Westminster Adoption Act 1947, which confirmed that the New Zealand Parliament alone made New Zealand laws
  • Māori, with the wars, confiscation legislation and native land legislation of the 1860s
  • the provincial governments, with their abolition in 1876
  • the appointed upper house, the Legislative Council, which was abolished by act of Parliament in 1950
  • the judiciary, with rejection of a 1985 white paper proposal to give the judiciary the power to strike down Parliament’s legislation.

Rights from God

In 1985 a white paper examined the proposed introduction of a bill of rights into New Zealand law. The parliamentary select committee dealing with the paper received 431 submissions, some of which contained unusual suggestions. Twenty-five of them stated that God should be acknowledged as the ultimate source of rights.

Westminster constitutional theory (based on the Westminster system of democratic parliamentary government in the UK) confers ‘sovereignty’ on Parliament – the power to make or unmake any law whatever. With one house of Parliament, no federalism (separate states), and no ability of the judiciary to strike down legislation, parliamentary sovereignty is stronger in New Zealand than in any other Westminster democracy. However, while Parliament is sovereign in New Zealand, for most of the 20th century its power was, in reality, exercised by the executive branch of government – the cabinet.

The rise and bridling of executive power

The executive branch

The executive branch of government, led by cabinet, executes or administers the law. It is the branch of government which does things, rather than passing or interpreting legislation (as Parliament and the courts do). The executive branch of government has always been strong in New Zealand, from the time when the governor was the only government.

Parliament took power from the executive in the 1850s. New Zealand’s cultural tendency to authoritarian government was evident in the 19th century, exemplified when Richard Seddon, popularly known as King Dick, was premier from 1893 to 1906. But, in the 20th century, executive administrations came to dominate Parliament and were able to control the power of parliamentary sovereignty.

Executive paradise

The existence of a stable two-party system from the 1930s to the 1990s meant that a single political party always had majority support in the small House of Representatives. A handful of ministers could dominate cabinet, cabinet could dominate the government caucus, and the government caucus could dominate the House of Representatives.

Early examples of Parliament delegating huge power to the executive were:

  • the Public Safety Conservation Act 1932, which gave cabinet the power to proclaim a state of emergency and make any regulations necessary to prohibit any acts which would be ‘injurious to the public safety’. It was first utilised at the outbreak of war in 1939, and was used aggressively during the 1951 waterfront industrial dispute. The act was repealed in 1987
  • the Economic Stabilisation Act 1948, which gave cabinet the power to make regulations as appeared ‘necessary or expedient’ for the purpose of promoting the economic stability of New Zealand. This power was used to institute a nationwide freeze on wages and prices from 1982 to 1984. The act was repealed in 1987.

The nation seemed relatively comfortable with the extent of executive power in New Zealand for most of this period, but abuses during Prime Minister Robert Muldoon’s 1975–84 administration led to a reaction.

Constitutional crisis

Immediately after the 1984 election the incoming Labour government wanted to devalue the New Zealand currency on the advice of Treasury and the Reserve Bank – New Zealand was in the midst of a currency crisis. However, the outgoing prime minister, Robert Muldoon, was reluctant to act. This caused a constitutional crisis because Muldoon initially refused to act according to constitutional convention. Muldoon eventually agreed to devaluation. Government caretaker conventions were clarified in the wake of this incident.

Bridling executive power

In the 1980s and early 1990s, a series of measures limited the scope of executive power:

  • the Official Information Act 1982 required the release of official information by the executive, unless there was good reason to withhold it
  • the recognition and reinterpretation of the Treaty of Waitangi in legislation from 1987 enabled enforcement of aspects of the treaty through the Waitangi Tribunal and the courts
  • the New Zealand Bill of Rights Act 1990 provided a means of upholding civil and political rights against the government through the courts
  • the Public Finance Act 1989 and the Fiscal Responsibility Act 1994 imposed financial disciplines on the accounting and reporting of public expenditure by the executive
  • an amendment to the Human Rights Act 1993 enabled legal claims to be brought that legislation was inconsistent with the right to freedom from discrimination.

Finally, and most significantly, the adoption of the mixed-member proportional (MMP) electoral system, following a referendum in 1993, reduced the likelihood of single-party majority governments in New Zealand. Since then parties have usually had to negotiate with other parties to form a government and to pass each piece of legislation.

Hononga, rauemi nō waho

More suggestions and sources

How to cite this page: Matthew Palmer, 'Constitution', Te Ara - the Encyclopedia of New Zealand, (accessed 21 June 2024)

He kōrero nā Matthew Palmer, i tāngia i te 20 o Hune 2012