Prime Minister Jacinda Ardern has warned travellers who flout self-isolation rules will be liable for deportation and face fines.

There would be "zero tolerance" for those who did not follow the rules of self-isolation and did not comply with with instructions from a medical officer of health.

"I consider this a message and a warning to those who come to New Zealand. We are a country who takes our role and responsibility of being hospitable very seriously. But in return we ask that visitors reciprocate. We will look after you, if you look after us."

"If you come here and have no intention of following our requests to self-isolate, frankly you are not welcome and out should leave before you are deported."

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This decision made by Cabinet on Monday reinforced how serious the Government was about protecting the health of New Zealanders, she said.

It would encourage visitors to comply with the rules or leave voluntarily if they did not wish to do so, she said.

MARK BAKER/AP Prime Minister Jacinda Ardern will not take a light approach to people ignoring the government's new travel restrictions.

"Remember anyone who is deported faces serious and ongoing consequences, including high chances of being refused future visa applications here and in many other countries," she said.

There were still only eight confirmed cases in New Zealand, but the global number jumped up by almost 11,000 overnight to 153,517, according to the World Health Organisation (WHO).

"Today most people in New Zealand were able to get up and go to work. This was not necessarily the case around the world … countries whose economies are effectively shutting down," Ardern said.

This was why the Government had decided to go hard and early and prioritise New Zealanders health by requiring everyone coming into the country (except from the pacific) to self-isolate, ban cruise ships and stepping up health measures at the border, she said.

"Slowing the transmission of Covid-19 and focusing on the health of New Zealanders is our best possible weapon in securing our economy for the long run."

The load on border control was likely to shift as the number of people coming into the country declined, so those staff could be deployed into areas of high demand such as deportation, she said.

"There will be a number of areas that you will see us looking to deploy Government staff."

Ardern earlier told Newstalk ZB that customs staff were now collecting the medical forms travellers were required to complete on arrival.

The measures, which have been replicated in Australia, were some of the toughest border restrictions in the world amid the pandemic, but Ardern stood by the decision.

"Everything we've done thus far, people will see we're not afraid to take decisive action, we're not afraid to be world first.

"My primary focus here, of course ... [is] keeping New Zealanders safe."

RICKY WILSON/STUFF Travellers entering New Zealand are now required to self-isolate.

She also told The AM Show the decisions made by the Government were based on expert advice. "We get the advice, we make the calls."

The restrictions would be reviewed in just over two weeks, but not lifted. "It is a point that we review our border controls, not necessarily lift them ... Everyone should prepare [for extensions]," she told The AM Show.

On Sunday, Auckland Airport was full of travellers trying to avoid the new rules, which took effect 1am on Monday morning. Cries of "we made it" could be heard from arrivals at the international terminal.

The new rules, which have been put in place to combat the spread of coronavirus, required every person entering New Zealand from anywhere in the world - excluding the Pacific - to distance themselves from others for 14 days.

Those in self-isolation should avoid social gatherings, work, school, child care facilities, university, religious gatherings, aged care and health facilities, prisons, sports gatherings, restaurants, and all public gatherings, according to the Ministry of Health website.

On Sunday, Ardern told TVNZ's Q+A that self-isolation did not mean you would be quarantined to your apartment, hotel room or home for 14 days straight.

"You can take a walk around the block, but you can't go into public places and places where you're interacting with others," she told Q+A.

Non-compliant people could face quarantine measures, which would require them to enter a medical facility to be monitored.

Ardern said the facilities wouldn't act like a prison, but authorities could make sure there were people at the door "to make sure you don't leave".

Ardern announced the new self-isolation rules on Saturday, saying they would slow down the spread of the virus.

The travel ban on China and Iran remained in place. Cruise ships were now banned from docking in New Zealand until at least June 30.

"New Zealand has today, relative to other countries, a small number of cases," Ardern said during the announcement.

"We must plan and prepare for more cases. We must go hard and we must go early. We must do everything we can to protect the health of New Zealanders."

If you are unsure if you should be self-isolating, contact Healthline for free on 0800 358 5453.