New Zealand's slow, staggered reopening to the world began at 11.59 last night with the Government lifting MIQ requirements for vaccinated citizens and permanent residents returning from Australia from today.

Auckland International Airport is not expecting the relaxed rules to lead to a flood of returning Kiwis. Just five flights from Australia will arrive on Monday, returning 910 passengers.

Auckland Airport general manager operations Anna Cassels-Brown put this low demand down to the fact that incoming arrivals will still have to self-isolate for seven days.

The airport expects to see 6700 international arrivals this week, just 10 per cent of pre-Covid transtasman travel numbers.

Cassels-Brown said the need for self-isolation will mean demand for travel will be very different to the demand experienced a year ago when the transtasman bubble opened.

"With self-isolation in place we're expecting a much more subdued response with only those New Zealanders who really need to travel making the journey across from Australia," she said.

Meanwhile, Cabinet will discuss and make decisions about the future of border restrictions today, Prime Minister Jacinda Ardern says.

Ardern told RNZ today the latest advice to the government from epidemiologist Sir David Skegg and his team - who have been advising the government on how to safely re-open the border - had been received late yesterday.

"We've been very much wanting to make sure that while we're in this period of dealing with Omicron that we're carefully easing up at the border so that we don't necessarily over-burden our health system, but with so many cases in New Zealand now, it makes sense to look at those settings.

"Cabinet will discuss and make decisions today," she said, adding that any decisions reached would be addressed at this afternoon's post-Cabinet press briefing.

The prime minister's comments came as tensions continued to simmer over the government's response to events both domestic and international.

Vaccine mandates also continue to be a sticking point, with the occupation of Parliament grounds entering its fourth week, and the High Court ruling that mandates for police and defence force staff are unlawful.

Ardern said the government was yet to decide whether to appeal Friday's decision but noted that four other court cases related to mandates had been upheld by the High Court.

"On this one, the judge has made the call that they are no longer justified in order to ensure business continuity."

There was no comment within the judgment about whether the mandates were justified at the time they were implemented, Ardern said, adding that police and the Defence Force had asked for the mandate to be applied to them because they had concerns around their business continuity.

"Theirs was a specific order. Health have a different rationale for theirs."

Ardern said the judge was "very explicit" that Friday's judgment wasn't "a judgment on mandates per se or the efficacy and importance of vaccines."

Addressing the country's surging current Covid-19 cases and hospitalisation rates, Ardern said she would not describe the numbers as "unexpected".

The increased use of rapid antigen testing (RATs) was providing a greater sense of the level of confirmed cases in the community, she said.

"Hospitalisations themselves will often tell you whether you're missing cases. But, at the moment, we're not vastly out of whack with what we've seen around the hospitalisation rates in other countries."

Number of daily cases hits almost 15,000

New Zealand's Omicron outbreak took off over the weekend with 14,941 community cases reported on Sunday, and a further 13,606 recorded on Saturday. Hospitalisations continued to surge with 305 reported in hospital yesterday, including in ICU or HDU.

There are currently 67,632 cases considered active, those which were identified in the past 21 days and not classified as recovered. That means nearly 80 per cent of the 85,667 cases recorded in New Zealand since the pandemic began are currently active.

The high caseload - and the fact many other countries are now climbing down from their Omicron peaks - means New Zealand now has one of the highest R rates in the world - a measure of the virus' reinfection rate.

Auckland University Associate Professor Siouxsie Wiles said the contrast of New Zealand's R value to the rest of the world currently came down to the fact that the country had been able to delay the entry of Omicron by two months.

"Many countries are much further into this Omicron wave – many countries had this kind of spread a month or so ago," she said.

As of Sunday, the Reff (effective reproductive number) for New Zealand stood at 4.23, according to a modeller from Rako science. This means each person with Covid passes it on to another 4.23 others.

National and Act repeated calls over the weekend for an accelerated border reopening and scrapping the self-isolation requirement in light of the Omicron outbreak.

National leader Christopher Luxon said the self-isolation requirements no longer made any sense, and were inconsistent with the rules within New Zealand, where only Covid cases and their household contacts were required to isolate.

"People arriving into New Zealand should have to take a test on arrival. If positive they should isolate. If not then they should be free to go about their business," Luxon said.

"The current rule is an unnecessary requirement that serves as a massive hurdle for Kiwis wanting to come home to visit family, or tourists wanting to come to New Zealand," he said.

Luxon also called for an accelerated reopening to foreign tourists, who are not allowed to enter the country until July.

Act leader David Seymour called for MIQ to be dumped, saying the rampant spread of Omicron in the community meant it made little sense to keep it.

"Under our new Omicron rules, only people with Covid and the people they live with have to isolate at home. But the Government is forcing everyone arriving into New Zealand - who have passed a pre-departure test - to isolate for seven days. It doesn't make any sense," Seymour told TVNZ's Q&A on Sunday.

Covid-19 Response Minister Chris Hipkins said the Government was getting updated advice on the risk to New Zealanders from people arriving from overseas given the recent steep rise in Omicron cases.

"We expect to be in a position to make an announcement very soon."

New Zealand currently has 1180 confirmed new daily Covid cases per million people - a number that exceeds that recorded in the European Union and the United States.

University of Otago Epidemiologist Dr Michael Baker said the Reff would continue to climb, but the currently high number was affected by the widespread introduction of rapid antigen tests.

"There was certainly a big jump, when those results came in that would have impacted our effective reproduction number," said Baker.

"The gradient is still meaningful, it is still telling us that we have got very intense transmission at the moment."

He said case numbers would continue to rise steeply and predicted the country could see tens of thousands of cases each day as we approach the peak.