Coronavirus: Jacinda Ardern rips into National for 'nonsense' COVID-19 speculation, focus on election

National's leaders have spent the first 24 hours of New Zealand's new COVID-19 outbreak peddling "nonsense" coronavirus claims and focusing on a potential election delay, the Prime Minister says.

Jacinda Ardern made the remarks in a press conference from the Beehive on Wednesday afternoon, telling reporters Judith Collins and Gerry Brownlee needed to focus their energy on the health response because "that's what New Zealand needs".

It comes after the pair criticised Ardern's handling of the coronavirus crisis, publicly speculating that she and Director-General of Health Dr Ashley Bloomfield may have known about the four new cases of community transmission days before the public was informed.

But the Prime Minister on Wednesday slammed that suggestion as nonsense, accusing the Opposition of politicking and urging unity from all sides of Parliament.

"The idea that we would keep information back from the public - when that is critical to us being able to look after their health, financial wellbeing and jobs - is just nonsense. This is the last I'll say on it," she said.

Collins has also been vocal about the general election in the last 24 hours, and in a press conference of her own on Wednesday she called on Ardern to postpone it until November or next year.

Ardern announced on Wednesday that the dissolution of Parliament has been delayed because of the outbreak - and if it's not dissolved by next Monday, she will have to choose an election date beyond the scheduled September 19.

But the Prime Minister hasn't been drawn into speculation about what decision she'll make. She says there will be time to deal with the election date in a few days, once the Government's had time to implement its resurgence plan.

And she asked the Opposition to "channel its energy" into helping the Government with the fight against COVID-19, rather than the election campaign.

"The sooner we can get on top of it, the sooner we can ensure the security of people's health [and] their livelihoods. After that, of course, that enables us to hold elections safely. That's where I would ask them to put their energy right now. That's what New Zealand needs."

Asked about National's complaints its new health spokesperson Dr Shane Reti hadn't received a COVID-19 briefing on Wednesday, Ardern said it's because there hadn't been "particularly anything new" beyond what was announced last night.

She noted that she'd called Collins to brief her on the renewed health crisis before announcing the four fresh cases of coronavirus and subsequent change in alert levels to the country at 9:15pm on Tuesday.

"I will continue to keep them informed, I will continue to let them know because this is a significant health issue," she said.

"All I'd ask in return is that we continue to see at least some unity in our response here. There should not be politics in this - this is a resurgence no one wanted.

"Let's work hard together to get on top of it, then we can get back to the normal resumption of whatever politicking the Opposition would like to engage in at that point."

On Tuesday, New Zealand's 102-day streak without a case of community transmission was broken when it was revealed four people from the same south Auckland family had contracted the disease.

Auckland's was escalated to COVID-19 alert level 3 at midday on Wednesday in response, with the rest of the country moving to alert level 2.

Auckland's level 3 lockdown is scheduled to end at midnight on Friday, but Prime Minister Jacinda Ardern has not ruled out extending it further if required.