Jacinda Ardern, David Clark 'weak' in COVID-19 debacle, but Dr Bloomfield shouldn't lose job - Todd Muller

Both Dr David Clark and Jacinda Ardern have been "weak" and should cop the blame for a blunder at the border that led to two new coronavirus cases, the leader of the Opposition believes.

The Health Minister has been guilty of not asking the right questions during the Government's recent COVID-19 debacle, Todd Muller says, while the Prime Minister has shown she's incapable of holding his feet to the fire over it.

But he says Director-General of Health Dr Ashley Bloomfield, the man responsible for heading up New Zealand's coronavirus response, should not lose his job over the botch-up.

Muller's comments come after two sisters, who later tested positive for coronavirus, were allowed to leave a managed isolation facility even though one was exhibiting symptoms and neither had been tested for the disease.

Despite the error, the National leader says Dr Bloomfield should now "spend every waking moment and more fixing it", rather than resign.

"You can't keep sacking everyone, but someone has to take accountability - and for goodness sake it's the [Health] Minister, because he hasn't asked the right questions," Muller told Magic Talk on Thursday afternoon.

"He hasn't said 'show me the data that confirms everyone's being tested'. If he knew how to be a minister, that's the [question] he would've been asking. Because he hasn't done that, it's clear mistakes have been made and he's none the wiser.

"That's not oversight from a ministerial perspective - that's weak."

Dr Clark has been guilty of "classic ministerial, running-the-other-way nonsense", Muller says.

"This is the most important issue in the country. We've got to protect our border - you're the minister."

And Muller reckons Prime Minister Ardern, whose job he's gunning for in this year's election, has also shown she's weak - though for a different reason.

"She just does not seem capable of holding feet to the fire and, if people don't deliver, sacking them," he continued.

"When I asked the Prime Minister [on Wednesday], 'these two haven't been tested, how many others haven't been?' she said 'sorry, we don't know the answer to that' - I mean, dear oh dear."

On Thursday, following a series of scathing attacks from the Opposition on the Government's handling of the latest COVID-19 issues, it was revealed National MP Chris Bishop had lobbied for the two women to be allowed to leave their managed isolation facility early.

Bishop told Newstalk ZB that the revelation was "a smear of an MP doing their job" - and on Thursday Muller told Magic Talk that the new information was "completely irrelevant".

"It's a failure of the Government's testing regime - it's got nothing to do with MPs saying it'd be nice for people to go to a funeral," he said.

"Once the decision was made to grant them bereavement leave, they needed to be tested before they left. Were they tested? No."