How long can I stay in New Zealand for? (Read Desc.)?

I was in NZ from Feb until March. I am planning on going back at the beginning of June. Since I was already there for 30 days, do I only have 60 days to spend there for the rest of the year? Or can I spend a 90 day visit every time I visit? Any information, or links that would help me out would be great! Thanks in advance.