Between 1845 and 1872, war was fought inside New Zealand. On one side were government forces, including British troops; on the other were some Māori iwi, while other iwi stayed neutral or sided with the Crown. At the heart of the fighting were two questions: who would keep their land, and who held authority in the country.

The first major conflict, the Northern War, began in the Bay of Islands in 1845 after the Ngāpuhi leader Hōne Heke and his allies cut down the British flagstaff at Kororāreka four times in protest, then attacked the town. Fighting began in Taranaki in 1860 over a disputed land purchase. In July 1863 government forces invaded the Waikato, the heartland of the Māori King movement, the Kīngitanga, which opposed selling land. The Waikato war ended after the battle of Ōrākau in 1864, and fighting elsewhere in the North Island continued until about 1872.

During and after the wars, the government used the New Zealand Settlements Act 1863 to confiscate huge areas of Māori land. This confiscation is known as raupatu, and it fell hardest on Waikato and Taranaki, taking in land of some iwi that had stayed neutral. The confiscations left a lasting sense of grievance. Many claims about this land have since been investigated by the Waitangi Tribunal, and the New Zealand Wars are now taught as a key part of the country's history.