New Zealan fuel canister style?

We use screw-on ones, though you can also buy the push-on ones. The screw on ones have a thread I'd guess a little over 1cm in diameter. I've seen Europeans using ones with smaller threads - about 6mm. They must also be available for sale somewhere (since the Europeans I;ve seen with them will not have been allowed to bring them from Europe by plane) but personally I have never seen those canisters with smaller threads for sale here. Hope that helps.

We took our MSR stove from USA to NZ and had no problems finding screw-on butane/propane canisters all over NZ, even finding MSR Isopro sometimes.

Great, sounds good. And good to know that there's more than one kind of screw on canister for future reference

I think what you might mean by "push on" is the old style of Butane canister where the can is punctured when it is first installed and then is not removed until empty. If so, I don't recommend pushing them on. The correct way is to unscrew the burner from the can attachment, strap in the can and then screw the burner back on. I have seen someone empty a whole can in one foul swoop by trying to push it on. Lucy there was no naked flame around because there would have been a hell of a fireball.

What annoyed me most was the habit shops have of sticking the price label over the bit you puncture. Even if you notice, and remember to remove the label, any remaining glue results in an imperfect seal, the loss of all you gas overnight, and a hell of a headache in the hut in the morning. Time to ban them and move to the modern safer alternative, I reckon.