NZ raptor. Species?

Lovely photo. I think it's a juvenile Swamp Harrier.

A harrier indeed. There are only 2 raptors in NZ and it is not a falcon

@Gondwana Thank you. I saw several of this species. They did not seem to have either the large wingspread of a harrier, or the flight pattern of the ones I have seen before. As I can only find reference to two raptors in NZ I am a bit confused! There does not seem to be any alternatives.