The country's border closed to foreign travellers for the first time at midnight.
The announcement was made at 6pm on Thursday, giving people planning to fly less than six hours' notice.
It's one of a series of drastic measures the government has taken this week as it attempts to keep Covid-19 at bay, including announcing a ban on indoor gatherings of more than 100 people.
RNZ's political editor Jane Patterson speaks to Philippa Tolley.
