The article below has references to polygamy among the New Zealand maori. Quite a long article but interesting insights if you have time to read it.
MAORI WOMEN IN TRADITIONAL FAMILY AND TRIBAL LIFE
This paper endeavours to reconstruct the role of women in traditional family and tribal life by collating and analysing the many references scattered throughout the ethnographic literature. As it follows the aims of recent monographs, one by Biggs focusing upon marriage,
1 and a second by Vayda, upon warfare
2 in traditional culture, it incorporates relevant data from these, particularly in regard to marriage.
The period to which the paper refers extends from 1769, when Captain James Cook rediscovered New Zealand, to approximately 1840, when New Zealand formally became a British colony.
...
Marriage Arrangements
The right of demonstrating preference in a love affair, or in making initial advances, was not restricted to men, and women frequently initiated liaisons.
46 Particularly where a woman was of higher rank than the man it might have been appropriate for her to do so.
47 She might publicly announce her choice to the tribe, or express her interest by such token gestures as squeezing the hand (
ropa) of the man in a crowd,
48 or pinching his knee;
49 when initial advances were neglected she might employ a go-between or close friend to assist.
50 Shame at rejection occasionally precipitated quarrelling among groups related to the individuals concerned.
When two sisters both expressed a strong desire to have the same man as husband, their father or an elder relative might arbitrate. In the story of Marutuahu, a man desired by both daughters of Ruahiore, the latter endeavoured to settle the argument by assigning Maru' to the younger; since the elder refused to abandon her claim he became husband to both. Marutuahu was not consulted during the discussion.