Auckland will move to alert level 2 at midnight tonight, the rest of the country will move to alert level 1.
A prominent epidemiologist thinks Cabinet ministers can still consider moving Auckland to alert level "2.5", despite the two further community cases confirmed today.
But Professor Michael Baker, of Otago University, added that depended on whether those new cases definitely were a result of the original three - and whether an indoor mandatory masking could be required.
Cabinet ministers are set to decide whether current alert levels should be shifted, as health officials race to trace the contacts of two Papatoetoe High School students who have just tested positive for Covid-19.
The new cases are students - a brother and sister who attend the school, which is now closed until at least Friday.
The sister is a classmate and close contact of the original case who tested positive last week.
It comes as ESR testing of wastewater has also found no evidence of any community cases of Covid-19.
Baker's fellow Otago epidemiologist, Professor Nick Wilson, initially responded to news of the new cases by suggesting lockdown continue for a few more days, given the lingering uncertainty.
Like Baker, he believed mask-wearing should be required around Auckland for the time being.
But Baker was relatively optimistic about Auckland's situation.
"The significance of these cases depends entirely on whether they were part of that broad net of contact tracing investigations - and it wouldn't be surprising you would get some secondary infections," he said.
"The pessimistic scenario would be that they are part of a chain of transmission that came to infect the family."
If that wasn't the case, Baker felt the two extra cases changed matters little.
"It's true that with every passing day, you get more confident that there isn't an undetected chain of transmission. So we're not totally clear, but I think it is looking more positive," he said.
"If this proves to be a border incursion or failure, it puts it into a manageable space that we have been in several times before."
Provided contact tracing investigations were adequate, Baker thought a continued high level of testing in Auckland and clear results from wastewater sampling could provide enough confidence to slightly lower the region's alert levels.
Baker said level 2.5 would mean mandatory mask use in indoor environments and restrictions on indoor gatherings.
"The only area I'm not sure about is whether travel restrictions in and out of Auckland would need to be kept in place - and this is why I think it's important the alert levels be carefully revised."
He stressed that people shouldn't see levels 2.5 or level 2 as level 1.
Like Baker, Covid-19 modeller Professor Shaun Hendy also said it was important to know whether the two cases were indeed "downstream" cases, or upstream ones.
"If it is the latter then this could be the sign of a significant cluster. If it's the former there is still a good chance the cluster is contained."
Otago University and ESR virologist Dr Jemma Geoghegan said she wasn't surprised that further cases had been detected.
"I don't think it's unexpected that we would have these cases. I think it would be more surprising if there weren't further cases."
Associate Professor Siouxsie Wiles said Cabinet's call came down to a risk assessment.
"The unfortunate thing over the last few days is, while we've got some information that is promising, it's not enough to help us really make a call either way," Wiles said.
"The worry is that, right now, if we move back down alert levels, we may have to move up again, given we are still within the incubation period of the virus.
"It will all come down to the Government's appetite for risk, as to what they decide to do."
