Two of the country's leading epidemiologists say today's high Covid-19 case numbers are simply the result of Auckland moving down alert levels, which has seen more contact between people.
And Professors Michael Baker and Michael Plank say it's likely case numbers could remain high - and also raise the stark possibility that Auckland would likely remain at level 3 for some time yet.
Director-general of health Dr Ashley Bloomfield announced 45 new Covid cases today and said it was the largest number in some time.
Thirty-three were household or close contacts of existing cases and weren't infectious in the community, while 12 were from two households.
Bloomfield said the high number was expected given the number of contacts that had been identified in the past. Twelve cases were also unlinked but for six, some links were visible.
Some were working in essential businesses during their infectious period.
Meanwhile, the Northland DHB is advising residents that a positive Auckland case that visited Kaitaia earlier this month was not infectious at the time, an investigation has shown.
"After our investigations, the clinical evidence we have suggests the case was not infectious while in Northland, and very likely acquired her infection after returning to Auckland," confirmed Dr Ankush Mittal, Public Health Medicine Specialist, Ngā Tai Ora - Public Health Northland.
There are no cases in Northland.
Professor Baker said he didn't want to be alarmist and would have to see two or three days straight with a high number of cases before determining it was a trend.
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However, he had been commenting for the past week about the likelihood of case numbers increasing if Auckland dropped an alert level.
"I have been talking for the past week about the problem of this long tail which has indicated ongoing transmission that we haven't been able to stop.
"It means there are cases out there in the community so, inevitably, moving from alert level 4 down to alert level 3 allows more transmission from those remaining cases into the wider community."
Baker said it takes about a week for a change in alert levels to realise as there are still infected people in the community.
"When you change alert levels, you're always looking backwards in time of seven to 10 days.
"People at alert level 3 start getting exposed, then you have the incubation period of five days and then you have to get sick enough to get tested, then you have an overnight test, a week later we finally see that [number].
"We might see the numbers just keep on climbing from now on.
"I would not regard this as a blip but this is the way we are going now. I would love to be proven wrong."
He said although it was not yet a trend, there was still potential for a move up in alert levels.
University of Canterbury modeller Professor Michael Plank said the surge in today's cases could be the first signs of the alert level change and, if so, could mean Auckland is stuck at alert level 3 for some time yet.
Plank said it could just be a "blip" due to the large number of household contacts being tested on the same day, but it was also possible it was the start of the impact of alert level 3 coming through in the case numbers.
Because some of these cases had been at work as it meant there was a higher risk the virus could spread thread it through workplaces and into other parts of the community. he said.
Plank warned moving to level 2 while there was still this level of community transmission would likely lead to a rapid increase in cases resulting in hospitalisations, which meant Auckland could be stuck at alert level 3 until it got its vaccination rate much higher.
Although he admitted it would be a hard sell, it was also possible Auckland could go back into level 4 if the Government tried to give elimination another crack and go "much harder".
Level 3 though might be enough to keep the outbreak in check and prevent it from growing really quickly.
"If numbers do start to trend upwards again, the Government faces some tough decisions. Reducing the alert level is likely to cause an explosion in cases and, with a large number of people either unvaccinated or yet to receive their second dose, the population is still vulnerable.
"Level 3 may be enough to keep the outbreak in check, but that could mean Auckland is stuck in level 3 for a long time until a lot more people have been able to get their second dose.
"The Delta variant is really good at finding unvaccinated people. So the message is clear: get vaccinated," he said.
Pacific health leader Dr Collin Tukuitonga was shocked at news of the 45 new cases.
"It was a shock, wasn't it? Dr Ashley tried to say it was to be expected, but that's a lot of new cases," he told the Herald.
"One hopes that this is not the trend back up again."
Asked whether he thought Auckland went to alert level 3 too early, there was a long pause before he said, somewhat humbly, that hindsight was a wonderful thing.
"We may have been too early."
Tukuitonga said a targeted lockdown of certain parts of Auckland could work if all of the cases were in one particular suburb, for example.
But with locations of interest popping up in west Auckland, the CBD, east Auckland and south Auckland, it appeared the cases could be spread around the city - and therefore a targeted lockdown approach would not work.
Asked if there could be a possibility of officials moving Auckland back up to alert level 4, he said: "If we get 100 cases tomorrow, then you might consider it.
"The problem for Government is they're concerned about business and income. That would just further wreck business.
"It would take a lot for the Government to do that."
Immunologist Dr Dianne Sika-Paotonu was worried by today's numbers.
"Unlinked mystery cases are continuing to appear which is also of concern and highlights the need for everyone to remain vigilant."
To keep New Zealand safe, she said high vaccination numbers must continue.
"It is critical that those who need to have a Covid-19 test still come forward to have this done, and should not be vilified in doing so."
Waipareira CEO John Tamihere said there is currently a "blanket of fatigue" across Tāmaki Makaurau.
As the holiday period creeps up on the country, he said it is time for the Government and New Zealand to start to learn to live with the virus.
However, he and staff at testing stations across the region have noticed a drop in numbers.
Earlier this month, health officials were concerned at sharp drop in testing numbers.
Dr Rawiri McKree Jansen, the clinical director of the National Hauora Coalition network of 54 practices, say outbreaks within vulnerable communities require "extra effort".
"Outbreaks in these communities will require extra effort, extra resources and service providers who are culturally concordant. It is in our collective interest to engage authentically and invest our efforts and resources to support these communities towards elimination or containment."
Act leader David Seymour says 45 new cases 43 days into a lockdown showed the Government's eradication strategy wasn't working, "it has lost control".
Delta has changed the costs and benefits of the Government's strategy. The lockdowns are no longer short and sharp, and the payoff of freedom no longer guaranteed.
"The Government now needs to show leadership and clarity. The eradication strategy won't work this time. We are going to change course. We must move from eradication to harm reduction."