Yes, there are many substantial ones in New Zealand. Lake Taupo is an obvious one, and there are some large ones in Otago and Southland which are not abutting the sea.

I would imagine Polynesian languages would distinguish between fresh water bodies and salt water ones, since they need to be able to drink. Even small islands can have pools.

[Edit to add: much of Polynesia is of volcanic origin, so freshwater crater lakes are a feature of these landscapes.]