About 120,000 New Zealanders served during the First World War, of whom 103,000 served overseas. When the war broke out in 1914 men flocked in their thousands to answer the call to arms. By the end of the first week of the war 14,000 had volunteered to enlist.
Despite confident claims that it would be 'over by Christmas', by 1916 the war appeared no closer to a conclusion. The seemingly endless toll in lives and maimed men began to impact on public sentiment. As the Census and Statistics Office was tasked with the compilation of manpower registers, newspaper editorials urged the public to accept the necessity of greater sacrifices if the war was to be won. Intensive campaigns to encourage enlistment failed to meet their targets, with only 30 percent of men eligible for military service volunteering.
In 1916 conscription for military service was introduced to maintain New Zealand's supply of reinforcements. Only four MPs opposed its introduction. The Military Service Act 1916 initially imposed conscription on Pākehā only, but this was extended to Māori in June 1917. More than 30,000 conscripts had joined the New Zealand Expeditionary Force by the end of the war.