New Zealand Prime Minister has announced that New Zealand's borders will close to visitors from 11.59pm tonight.

This also extends to Pacific nations, with the exception of those needing to travel on humanitarian grounds.

New Zealand citizens, permanent residents and their children and partners, will continue to be allowed to return.There will also be exemptions for key workers in the health sector.

Ms Ardern said spot checks had shown returning New Zealanders were complying with the requirement to self-isolate for 14 days but that was not always the case with visitors.

"I have been increasingly concerned that visitors to New Zealand have not necessarily adequately isolated for 14 days or are choosing not to that is an unacceptable risk that we must end."

It was critical to slow the spread of COVID-19 to manageable "waves" so the health system was not overwhelmed, she said.

"I'm not willing to tolerate risk at our borders."

"If we manage to slow down the transmission of this virus in New Zealand, that is how we will protect jobs and the economy."

Ms Ardern stressed the restrictions applied to people, not products. Freight would continue to be allowed in and supermarkets would have everything people needed as long as they were given the chance to restock.