Prime Minister Jacinda Ardern will meet with her Cabinet on Wednesday afternoon after receiving the latest test results and advice from the Ministry of Health on the family of Covid-19 cases in Auckland.

At 4.30pm on Wednesday Ardern will update the country on whether the alert level 3 for Auckland and alert level 2 for the rest of the country would be extended past midnight, when it is currently due to expire.

If the decision is a step down of alert levels, it is likely Auckland will not go straight to level 1, as the Government has never moved down more than one alert level at once.

On Tuesday no further cases of Covid-19 had been found in the community beyond the three inside a single family, despite tests of tens of close contacts, thousands of community tests, and testing of the water in Auckland. Some tests of contacts were still pending.

Event promoters around the country will be watching the announcement with bated breath, as even level 2 bans any gatherings of more than 100 people.

Rodney Jones, an economist and modeller who has been an informal advisor to the Government throughout the pandemic, said there was a strong possibility the lockdown had been a false alarm.

“If it’s zero cases again tomorrow this has been a false alarm – no worse than Northland,” Jones told Stuff.

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He was referring to the recent case of a returnee developing Covid-19 after leaving managed isolation and travelling to Northland, which did not lead to a community outbreak.

Jones said there was a clear pattern that emerged in recent serious outbreaks like those in Australia – a large amount of recorded cases in the days after identification.

“You get a whole bunch of cases at the start. You get two or three cases on day one, then maybe 10 or 12 on day two, as you start to test the pool where there’s likely to have been community transmission...Here we’ve had three then zero zero.”

He differentiated between cases of “leakage” such as the Northland case and outbreaks such as August, and said there was a strong case for optimism as despite the new variants of Covid-19 global infections were trending down.

Because of this, if there was another day with zero cases Jones thought New Zealand could move down the alert levels fairly rapidly.

But University of Otago epidemiology professor Michael Baker made a case for more caution to Stuff.

Much of the caution was centred around the mystery of the infection in the first place. One of the family works with laundry from incoming flights, but has no in-person connection to the border, meaning officials are still not certain that she caught the virus from the border, rather than an unknown community case.

Baker said the most plausible scenario was some kind of border failure that had seen the mother infected – meaning a wider community outbreak was unlikely.

“The border failure scenario is most likely, based on past experience, they happen every two or three weeks and some of them behave like this,” Baker said.

But he said there was still a plausible scenario where the case was the “tip of an iceberg” of an unknown community outbreak.

“In general you should plan for the more pessimistic scenario – which would be community transmission, which is still quite a plausible scenario.”

Baker said the decision would be whether to extend level 3 for a few days or not, and it would be a “calculated risk” to move Auckland down from level 3.

Given the mystery of the infection, he suggested that the most the Government should consider would be a move to level 2.5 in Auckland, with a strong emphasis on mask use in indoor spaces.

Baker said the alert level system itself was overdue an overhaul.

University of Auckland modeller Dr Shaun Hendy said that if there was another day with no cases found there would be a strong case to move down alert levels.

“I think on balance the evidence is pointing towards the fact we are dealing with a more isolated cluster.”

Jones said the official policy and advice surrounding it was sometimes a bit stuck in the rearview mirror and New Zealand would need to adapt its strategy to 2021, and not just focus on what had worked well in 2020.

“We have to start looking forward. We should be more optimistic,” Jones said.

“I think there's been a lot of expression of anxiety that is not based on where we are, facts-wise.”

National's Michael Woodhouse said on Tuesday the country was “running out of patience with alert level rises.”

“At some point a Government, probably this Government, will have to take the tough decision to say, ‘Covid is endemic on this planet, and we need to take different steps,’ but in the meantime, while we pursue an elimination strategy, the Government has got to get it right,” Woodhouse said.

Covid-19 Response Minister Chris Hipkins said the Government had been “very precautionary” and said New Zealand kept seeing infections that were "highly unlikely” – because it had cut out the more likely routes of transmission.

“As we roll out the vaccines, the risk will still be with us and we still need to be willing to respond when we need to.”