New Zealand was governed as an autonomous dominion of the British Empire. A national assembly was elected by universal suffrage but women were not allowed to become representatives. William Ferguson Massey, the leader of the Conservative Reform Party, was appointed prime minister in July 1912.

In 1914 New Zealand had a population of just over 1.1 million. Most of the population were the result of British emigration but there were also about 50,000 Maoris.

From the age of 12 all males in New Zealand received military training. In 1911 New Zealand formed a 25,000, part-time national militia. Most of the men who volunteered to join the New Zealand Expeditionary Force (NZEF) in August 1914 came from this Territorial Army.