Air New Zealand Air Points - Unused Air Points account

So for some reason I have an Air Points account. I am a USA resident. I think I opened it (having the $50 fee waived) when I was on a NZ business class ticket not credited to NZ. However, there's never been any activity in it and I don't foresee crediting any NZ flights to it in the next few years.

Will I still get charged the "account inactivity" fee after 2 or 3 years, and if so, what form will that take since I have no Air Points Dollars? Will they send me a bill?

I expect they'll just close the account due to insufficient funds to pay the annual no-fly NZ fee (assuming this is being enforced).

I think you account will remain zero balance until they decide to close your account. I have a friend whose Airpoints account went to negative a few years ago because of no activity and then they decided to credit him a few months later and his account has remained zero since.