The life of a Parliament can be terminated either by dissolution or expiry. The Constitution Act provides that the Governor-General may, at his pleasure, dissolve the General Assembly. Today, in this as in all other matters, he is bound to accept the advice of his Ministers while they have a majority in Parliament. A Parliament expires, under the Electoral Act 1956, three years after the day fixed for the return of writs at the previous general election. The Constitution Act of 1852 had fixed the maximum life of Parliament at five years, but the Triennial Act of 1879 provided for the three-year term which has been the rule since. The 1931 Parliament did pass a quadrennial Act but the 1935 Parliament restored the triennial system.

In practice Parliament is not normally allowed to expire. A few weeks before the expiry date the adjournment of the House is moved and a dissolution is requested during the adjournment. The total period which may legally be allowed to elapse between the end of a Parliament and the issue of writs for elections to a new Parliament is 10 days. The adjournment procedure provides members with a break before elections and brings Parliament to a planned end. Within recent years only one Parliament has been dissolved before entering its third year. The twenty-ninth Parliament was dissolved in 1951, after approximately 20 months, in order to obtain the verdict of the electorate on measures used in dealing with a major strike.

Before the 1956 Electoral Act a parliament had the undoubted power to extend its own life by statute. The parliaments elected in 1914, 1931, 1938, and 1951 demonstrated this. One can only speculate whether future Parliaments might feel inhibited by the 1956 Act from passing similar legislation unless supported by a 75 per cent majority.

New Zealand's experience cannot be said to have demonstrated the superiority of the triennial system over a quadrennial system. Expert legal, political, and economic opinion has frequently been expressed in favour of increasing the length of the Parliamentary term. In particular, it has been pointed out that deficit financing in election years has produced triennial economic crises and has helped to reduce New Zealand's rate of economic growth.

Size of the House of Representatives

There are 80 members of the House of Representatives – 76 Europeans and four Maoris. They are designated “members of Parliament”. Members who are serving on the Executive Council are also termed “honourable” and there is a convention that Her Majesty be requested to allow the title to be retained by a member who has served three years on the Executive Council. The number of members authorised by the Constitution Act was not more than 42 and not less than 24. The first Parliament, in 1854, comprised 37 members. Numbers were increased by legislation in the next two decades, European representation reaching its maximum in 1881 when there was provision for 95 members, including four Maoris. The Maori representation of four members was fixed in 1867 and has been retained in current legislation. The number of European members was reduced in 1887 to 70 and raised again to 76 in 1900, at which figure it has remained. Subject to certain disqualifications any registered elector, and only registered electors, may stand for Parliament. There are no residence qualifications, though, in practice, local candidates tend to be preferred by party selection committees.

Because New Zealand has a population of less than two and a half million, each member of Parliament represents approximately 25,000 people. By comparison with the United Kingdom, where the proportion is approximately one member per 80,000, the New Zealander is well represented. But the scope of Government activity is wide and throws a considerable burden on so small a number of members.

In 1965 the Electoral Act was amended for the purpose of stabilising the South Island electorates at 25. Those in the North Island would increase in accordance with population growth.