COVID-19: Christopher Luxon, David Seymour grill Jacinda Ardern for doing 'nothing to prepare for Omicron'

Once Omicron enters the community, the whole country will move into the 'red' traffic light setting - and that could be any day now, with three confirmed and one possible case in Auckland and another in Palmerston North.

For now, Northland will join the rest of New Zealand in 'orange' at midnight. 

Prime Minister Jacinda Ardern says that in the event of an Omicron outbreak, cases could surge from hundreds to thousands in as little as a fortnight. 

But she's ruled out using lockdowns to control the variant's speed. 

Labour MPs were in mufti and mingling over muffins at morning tea on Thursday, making the most of the stunning Taranaki backdrop of the party's annual caucus getaway. 

But while the shorts and jandals say summer holiday, it was back to school for the caucus, and the project from their leader this year was to stay humble.

"As we humble ourselves, we demonstrate the privilege that we have to be in this role, and we crack on with the work of 2022," she said in her speech to the caucus. 

That work had already begun with the changing of the traffic lights. 

"Northland will join the rest of the country in orange at 11:59pm tonight," Ardern announced at her afternoon press conference. 

She's keeping all of New Zealand at orange as we prepare for an inevitable Omicron outbreak. 

"When Omicron enters the community - beyond border-related cases - the whole country will move into red within 24-48 hours," Ardern said. 

But it's farewell to domestic borders and widespread lockdowns. 

"We don't have regional boundaries as part of the COVID Protection Framework."

Ardern urged Kiwis to have a plan for when they get sick or are exposed and have to be isolated, because when Omicron breaks through our border fortress, the sickness will spread far and wide and quickly. 

"I think it's quite likely that we could see cases in the thousands, if not tens of thousands a day, in the peak of an Omicron wave," says Professor Michael Plank. 

The Prime Minister says booster shots could slow it down. 

To check who's Omicron-positive, there will be wider access to free rapid antigen tests. As for who will need one, the priority will be the symptomatic, vulnerable, essential workers and close contacts. 

But the Opposition is asking: where's the detail?

"There wasn't a plan for Delta, it was made up on the fly," said National leader Christopher Luxon. "Here we go again."

ACT leader David Seymour shared a similar sentiment.

"The Government has done nothing to prepare for Omicron."

Ardern said the Government has "a broad plan" and will be providing more details of that next week - promising the Government hasn't just been on holiday mode all summer.