Compulsory military service has been adopted in New Zealand on a number of occasions. Under the Militia Ordinances of 1845 and 1858 it was enacted that European males should be trained to form an effective military force for the defence of lives and property within the colony. All between the ages of 18 and 60 were liable for service under the 1845 Ordinance, though on no account could they serve beyond a certain distance from their local police office. The 1858 Act of the New Zealand Parliament divided militiamen into three classes – the first class comprised unmarried men and widowers; the second class were married men and widowers with dependants; and the third, reserve men, were all men between 16 and 40 years of age. Whenever only a portion of the militia was required, volunteers were first called for and the balance was obtained by a ballot of the first class. Training was set at 168 hours a year, instead of 28 days as prescribed in the 1845 Ordinance. Militia districts were reduced from a 25–mile radius to 15 miles, and battalions were frequently called out in North Island districts. The militia was disbanded in 1872, although statutory provisions for its reconstitution remained in force.

From the Maori Wars until 1910 the volunteer system provided New Zealand's principal means of defence.After the South African War and particularly after the granting of Dominion status in 1907, colonists began to see international affairs from an Imperial viewpoint. They realised that any dispute involving Britain also concerned her Empire and that this might necessitate New Zealand troops serving overseas. As the volunteer system appeared to have outlasted its usefulness, the Council of Defence – formed in 1907–advised a return to compulsory enlistment “whereby the burden of service in the defence force will be more evenly distributed”. For some years prior to 1908 compulsory military training had been argued in the country and public opinion had been gradually won over. This was due, principally, to vigorous propaganda campaigns undertaken by the National Defence League, an organisation led by Lieutenant-Colonel Allen Bell, of the Auckland Mounted Rifles.