Jacinda Ardern says the Government's COVID-19 vaccine mandates remain important due to the more severe Delta coronavirus variant still circulating in the community - despite Omicron being the dominant strain.
The Prime Minister's comments come after ACT Party leader David Seymour said it may be time for the Government to move on from vaccine mandates.
During her weekly interview with AM, Ardern was asked what the impact on COVID cases and hospitalisations would be should the vaccine mandates be removed.
Vaccinations against COVID-19 have been mandated by the Government for workers in certain industries and roles, with redeployment off the front lines possible for those who refuse, to help reduce the impact of the virus that's killed more than 5.8 million people and infected nearly 423 million around the world.
The mandates have sparked 13 days of protest outside Parliament, where people have camped out demanding an end to them and other COVID-19 restrictions. Police and protesters faced off in the early hours of Monday - the 14th day of occupation.
"Mandates, the role that they play; firstly, there is with vaccines a reduction in transmission as a result of being vaccinated," Ardern said on Monday. "With Omicron, it's less than it was for Delta but still some studies suggest about a 50 percent reduction."
According to a recent study out of Denmark, Omicron was 2.7 to 3.7 times more infectious than the Delta variant among vaccinated Danes. That suggests Omicron mainly spreads more rapidly because it is better at evading immunity obtained from vaccines.
The study found booster-vaccinated people are less likely to transmit the virus, regardless of the variant.
Research has also shown that Omicron, while more transmissible, appears to result in less severe disease than the Delta variant - the strain circulating in New Zealand during last year's COVID-19 lockdowns.
Twenty-seven New Zealanders died during the 2021 Delta outbreak but no patients have died with Omicron. As of Sunday, 100 people were in hospitals, though none were in intensive care.
"The second reason mandates have been important is we still do have Delta in New Zealand," said Ardern. "In fact, we're still seeing caseloads in hospitals of Delta."
Ministry of Health data supplied to TVNZ last week showed there had been 1315 cases of Omicron reported in New Zealand since January 1 and 435 Delta infections.
Ardern said another justification for vaccine mandates was the "significant reduction" in hospitlisations. US studies show a booster jab from a vaccine such as Pfizer - the predominant vaccine used in New Zealand - provides 90 percent protection against COVID-19 hospitalisation.
"We want to make sure we don't overwhelm our hospitals and our health care so those are some of the primary reasons [for mandates]... right when we're taking off is not the time to remove those things," Ardern said.
Seymour said on Sunday vaccination rates were making "little difference" to infection rates with Omicron.
"If there is little difference in the rates of infection and spread of Omicron between vaccinated and unvaccinated people, then what is the point of segregating them?" Seymour asked.
"It is time to weigh up the costs that vaccine requirements are placing on individuals, on workplaces, and on social cohesion, and ask whether policies that force vaccination in various settings are still worth it."
Those comments were condemned by COVID-19 Response Minister Chris Hipkins, who accused Seymour of "dog-whistling to anti-vaxxers".
"The Government has always been of the view that mandates are a temporary measure to keep people safe but moving into an Omicron surge, as we are, is not the time to end them," Hipkins said.