NZs response all the way through the Chinapox situation has been to pull up the drawbridge to keep it out, stamping down hard on any instances. Ms. Ardern (PM) stated recently that NZ would not be reopening their borders until next year. Seems part of this is that NZ is slow at getting a vaccination program up & running (around 20% of adults done so far) & their healthcare system isn't as extensive as ours.
My brother & family are NZ citizens & live in Auckland, so I get updates on the situation over there. His take is that most of the cases that have come in there are returning NZ ex-pats (pretty well the only people allowed in anyway) not taking the mandatory quarantining seriously.