NZ isn't some 3rd world country where someone who broke the law can flee. There are plenty of cases where a non-citizen breaks US Law (ex: Sanctions) and is arrested outside of the USA.
The United States and New Zealand have a number of agreements in place to fight crime and are both are members of the Five Eyes intelligence alliance.
sorry but this makes no sense: if you infrange a US law, but you neither are a US resident or citizen, or you never even been there, why this law should apply to you?
perhaps nz is indeed a US protectorate if it allows this