There was no one date for the arrival of the major settlement arrivals in NZ of the Maori. Each iwi have their own traditions. It is known that for some, that when they arrived, they discovered earlier arrivals in residence.
The earlier Great Fleet ideas are now considered romantic fiction.
The earliest dated sites for settlement in NZ are two in the South Island, one at Wairau Bar in Marlborough, and the other at Shag River mouth in Otago. These date to the 1300s. See teara.govt for more info which represents modern consensus of opinion.
There would almost certainly have been early isolated exploration expeditions, but any settlements subsequent to the exploration are yet to be discovered. These putative sites may have been destroyed by erosion or volcanic activity - who knows.