Who Was The First To Invade New Zealand,also When And Why?

Well New Zealand was first occupied by the Maori's that are believed to have come from the islands close to New Zealand. They are driven away from their original home for several different reasons. (may only be one or two of these factors)

1. Overpopulation
2. The need to explore
3. Food Shortages.
4. Natural disaster damage
5. Or other Migration factors you might think of.

Then a dutch man, Abel Tasman, discovered New Zealand for western civilisation, only to be scared off by the Maori's.

After that Captain Cook arrived, he was successful in befriending the Maori's and it went on from there.

Hope that helped. And also accurate, because that's what I have been told in my Social Science class.