PM Jacinda Ardern traded verbal blows with National leader Judith Collins and deputy leader Gerry Brownlee, with the Prime Minister accused of lacking transparency and sitting on information.

As major parties suspended their election campaigns, Collins urged Ardern to push back the election date given the alert level restrictions and the media spotlight on the Prime Minister.

She said there was a lack of transparency because the Opposition should be provided more information, and should be consulted on such major decisions.

Brownlee added that it was "interesting" Kiwis were warned there could be another outbreak about 10 days ago and told to stock up on masks.

"And then you had the Prime Minister's visit to the mask factory [on Tuesday] ... all very interesting things to have happened a matter of hours before a large residential area of New Zealand went into level 3 lockdown."

Brownlee told Newstalk ZB's Mike Hosking today that the election was now a distraction to the fight against Covid-19. "Regardless of how we got here... it's very serious. Although it's Auckland locked down, the rest of the country is also affected."

Ardern said the suggestion the Government was holding back vital information was "just nonsense".

"There is no reason why we would ever do that ... I do worry that those kinds of theories do nothing to support what needs to be collective action from all of us."

She said the caretaker convention, which would normally mean consulting the Opposition in major Government decisions, only applied after an election was held and before an administration was formed.

"We'll keep the National Party informed. All I ask in return is that we continue to see some unity in our response here."

• Heather du Plessis-Allan: We need to consider delaying the election

Asked about the election date, Ardern said the dissolution of Parliament had been deferred until Monday to provide some breathing space to focus on the Covid response.