New Zealand in fresh Omicron scare

Central Auckland
There have been six confirmed cases of the Omicron variant of COVID-19 in New Zealand to date. -AP

Jacinda Ardern has warned New Zealanders to brace themselves for new daily COVID-19 case records when - and not if - Omicron runs loose in the community.

After a summer free of the ultra-transmissible variant, health authorities fear that moment may have arrived after two further positive results were reported on Wednesday night.

The health ministry issued an urgent release at 11pm confirming genomic sequencing results of an Auckland airport worker and a household member of a quarantine worker.

It has urged Tuesday lunchtime diners at the Ara Tai Cafe, a seaside cafe in the Auckland suburb of Half Moon Bay, to isolate immediately and get tested.

The health order applies only to inside diners, rather than those eating outside.

There have been six confirmed Omicron cases in NZ to date, but so far, there has been no documented community transmission outside of households.

Speaking from at Labour's year-starting caucus retreat near New Plymouth, Ms Ardern said Omicron's arrival was inevitable.

"We know Omicron is in every corner of the world at the moment," the prime minister said.

"We know that we will experience in New Zealand cases at a level we haven't experienced before. We face a different challenge with Omicron ... it is not insurmountable but it is a different foe.

"We know again the tools that will make a difference. Vaccination will change the game. For the most part, people will be able to recover at home. They won't experience severe disease and illness.

"That's not something we could have said in 2020."

University of Otago public health professor Michael Baker is "very concerned" the transmissible variant may now take hold in the community.

"We've had three of these near misses through different pathways," he told Radio NZ.

"A huge driver is the really large number of infected cases in New Zealand. We've never had such pressure on our borders."

With Omicron surging in Australia and other countries, cases are arriving in quarantine at record rates for NZ.

The seven-day rolling average of border cases has overtaken the same average of daily community cases, heaping pressure on the system.

"We need to reduce the flow of infected people into New Zealand immediately," Dr Baker said.