Mokai - Slavery in Colonial Times
As in many other cultures, slavery was a key element of Maori society. Mokai (servants or slaves) were usually spoils of war, condemned to lives of drudgery, danger, heavy physical work and obedience to their masters or mistresses' whims; they were expected to fight under supervision, could be used to negotiate with enemies, or as food if supplies were short. Female slaves might be prostitutes, or become secondary wives to their conquerors. Marriages between victorious chiefs and highborn women of defeated tribes strengthened the invaders' right to the land.
http://www.theprow.org.nz/maori/slavery-in-colonial-times/