New Zealand has closed its borders to everyone but citizens and residents in an attempt to stop the spread of coronavirus.

The ban applied to planes boarding after 11.59pm on Thursday - any planes in the air already would not be impacted.

Partners and children of citizens or residents are exempt from the ban, as are some health and humanitarian workers. A full list of exemptions is available here.

The announcement followed a coronavirus cabinet meeting on Thursday and came minutes after Australia banned all non-residents from its country.

ROSA WOODS/STUFF Prime Minister Jacinda Ardern announced the Government would shut the border to tourists and temporary visa holders on Thursday.

Prime Minister Jacinda Ardern made the announcement on Thursday evening, acknowledging this was an unprecedented move in New Zealand's history - but a necessary one as the virus spread in other countries.

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"This will stop tourists, or temporary visa-holders, including students or temporary workers, from coming to or entering New Zealand.

"New Zealand residents and citizens will be able to return. And of course that applies to the children and partners of residents or citizens."

Australian residents who are "usually resident in New Zealand" are exempt.

Ardern said, given that all 28 confirmed cases of coronavirus related to overseas travel, the risk was too great.

"All of the cases of COVID-19 identified in New Zealand relate to people travelling to New Zealand and bringing the virus with them – therefore we need to further restrict the risk of people bringing the virus into New Zealand," Ardern said.

"All of the evidence to date is that returning New Zealanders understand the requirement for self-isolation but I have become increasingly concerned that visitors to the country either may not be able to adequately self-isolate for 14 days or chose not to and that is an unacceptable risk that we must eliminate.

"A small number of exemptions to the new measures can be sought for humanitarian reasons, essential health workers and citizens of Samoa and Tonga who need to travel to New Zealand for essential reasons."

She was not pleased with the amount of information being given to tourists as they arrived in New Zealand and could not tolerate any risk there.

"I'm not willing to have risks here, and that's why we're making this decision tonight."

She had discussed the move with Australian Prime Minister Scott Morrison but did not know about his similar call for Australia before making her own.

The decision was made between 4pm and 5pm on Thursday.

Unlike the earlier self-isolation restriction, this move covers the Pacific.

Ardern was confident that some flights would remain for the estimated 100,000 Kiwis travelling overseas.

This was because freight was still being flown into New Zealand.

Foreign Affairs Minister Winston Peters has mooted "mercy flights" for Kiwis stuck overseas if needed.

There are now 28 confirmed cases of coronavirus in New Zealand, all of them related to recent overseas travel.

Many, but not all of the cases have been citizens or New Zealand permanent residents.

At least three cases of Covid-19 in New Zealand have been travellers from abroad.

RICKY WILSON/STUFF Passengers entering New Zealand will face an extra station prior to immigration where health officials will question them about Covid-19.

On Thursday, a case in Rotorua was confirmed by local public health officials to be a French national who arrived in New Zealand on March 13, and was tested prior to arriving in the town.

An Australian man, Andre Reynaud, entered self-isolation after testing positive for Covid-19 on Saturday. He had taken the test while in Australia, and learned he was positive while eating at a Wellington cafe.

A woman from Denmark was the eighth confirmed case in New Zealand. She arrived on March 10, flying from Auckland to Christchurch and travelling to Queenstown in a rental vehicle.

The Government on Saturday announced that all travellers into New Zealand must self-isolate for 14 days.

It announced earlier on Thursday that all indoor gatherings of more than 100 people would be banned.

National party leader Simon Bridges called on the Government to shut down all borders to anyone but permanent residents and citizens late on Thursday afternoon.

Since Monday, passengers entering New Zealand have been required to fill out a questionnaire declaring places they have recently travelled, any connections they may have had with people diagnosed with Covid-19 and whether they are experiencing any symptoms.

An extra station has been implemented before the immigration counters at Auckland International Airport, where passengers will be assessed by a health official.

Any passengers with symptoms of coronavirus, including fever, coughing and breathing difficulties, will be escorted to a private area to establish whether they need to be transported to hospital for testing.

Hand sanitiser stations, some with up to four pumps in a row, have been set up around the airport.

Signage with coronavirus warnings, information about the compulsory 14-day isolation period and numbers for relevant health authorities are placed throughout, including huge screens on walls and at the baggage carousels.

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