Prime Minister Jacinda Ardern says it would take "an extraordinary circumstance" for measures such as border closures and lockdowns to be re-introduced.

Her comments come after the Government overnight retired the Covid-19 Protection Framework, or traffic light system, removing most mask requirements and the ability for the Government to introduce measures like gathering restrictions.

All Government vaccine mandates will end on September 26, including those for new arrivals in the country. Employers can continue their own mandates.

The decision has received support from business and the political right but the lack of a framework has left some health experts concerned about the ability to tackle future outbreaks.

Ardern said even in the eventuality new variants arriving it would take something "extraordinary" to ever again consider tougher measures including lockdowns and border controls.

"If you were to see, for instance, the set of circumstances that would trigger countries to start thinking about those extraordinary measures, it would be an extraordinary circumstance.

"If you saw that kind of scenario, it would be if the entire world was shifting as well. That's not the kind of scenario we are anticipating based on the trajectory of the virus that we have seen."

Prime Minister Jacinda Ardern during the post-Cabinet press conference with Covid-19 Response Minister Ayesha Verrall. Photo / Mark Mitchell

She said the old tools for keeping Covid-19 at bay – such as border closures and lockdowns – were less effective with more transmissible variants.

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"One of the issues with Covid is that over time the variants that take over, take over because they are more transmissible.

"So by default some of those measures like lockdowns and border closures, they just don't work in the same way."

Asked what ongoing vaccinations rollout was planned, Ardern said it was still an important part of the overall protection.

"We will of course continue to look at all the developments in vaccination as well."

National leader Christopher Luxon said his party was "very supportive" of the loosening of restrictions yesterday.

"They're long overdue frankly. It's good we're moving on and joining the rest of the world."

In response to fears from the disabled and immunocompromised that loosening restrictions would increase their likelihood of getting sick, Luxon said "it's about personal choice".

"It was always interesting to me, travelling in Asia a lot, you would see people post-SARS wear masks and take responsibility for their own health and the health of others as well."

National leader Christopher Luxon. Photo / Mark Mitchell

Luxon alluded to potentially scrapping the Covid-19 response shadow portfolio currently held by Chris Bishop.

"We'll look at all of that towards the end of the year. As I said at the very beginning, that's when we'll have our next performance reviews of our MPs and we'll make sure we have the settings right and the right people on the right assignments," Luxon said.

Act leader David Seymour welcomed the end of Covid restrictions which "the Government has clung on to for far too long".

He called for an independent investigation into the Government's Covid response to fully understand the damage the restrictions had caused.

Meanwhile, Green Party spokesman for Covid-19 Teanau Tuiono said strong public health measures remained essential and today's decision would leave people wondering if the Government had given up.

His comments reflect concerns raised by public health experts about the lack of a new framework to counter future waves of new variants.

Some health organisations and disability advocates have also voiced concerns about removing vaccine mandates and the impacts on vulnerable and immunocompromised people.

Covid-19 Response Minister Ayesha Verrall said on the vaccine mandates they needed to ensure all limitations on people's ability to work were "justifiable and proportionate".

Contrary to when the mandates were introduced, the vaccine did not now reduce transmission of Covid entirely, she said.

The workforce also now had high rates of vaccination and immunity from infection.

"So we weren't having the benefit that we expected from vaccination alone to be able to sustain the mandate."

In terms of future variants, Verrall said the focus was still on high rates of vaccination, access to masks and rapid antigen tests, and access to antiviral treatments.

Asked about pleas from experts to improve ventilation before reducing mask requirements, Verrall said she continued "exploring options" but given the amount of work required it was not realistic to wait for those changes to occur.

- Thomas Coughlan , Claire Trevett and Michael Neilson, NZ Herald