You can get the free Netflix app for i-Pad on the US App Store but not on the NZ one. Assuming you are currently using a NZ-based i-Tunes log-in, log out of that and create another/new i-Tunes account specifying USA as the country in which you are based. I think you will need a different email address. Then download the app.

I used my YouShop physical address and ZIP code etc to open the new account. I use my xtra email address for my NZ i-Tunes account and a gmail address for my US account. You don't need to load a credit card number to open the US account. You can then swap between NZ and US App Stores whenever you want.