A Covid-19 modelling expert says moving Auckland alert level 3 is a "calculated risk" and we could easily bounce back to level 4 in a matter of weeks.
Prime Minister Jacinda Ardern announced this afternoon, after a five-week strict lockdown, Auckland would move to alert level 3 for at least two weeks from 11.59 pm tomorrow night.
But experts stressed the success of continuing to stamp out the virus would depend on whether people followed the rules.
Te Pūnaha Matatini Covid-19 modeller Professor Michael Plank said although the majority of cases were under control and were household or known contacts, we were still seeing some spread between households and it was proving difficult to stamp out.
"There is a danger in level 3 that an increase in the number of people that were out and about could just make that spread between households all the more difficult to ringfence," he said.
Plank said people meeting up with friends and family members not in their bubble was our biggest risk.
"It's really important that people don't take this reduction in alert level as a signal danger has passed."
Plank said this was a really tough decision for the Government to make as five weeks was a long time for people to be in strict lockdown and people were tired.
"The Government is trying to balance a range of factors so it is a complex decision and a very tough call."
University of Otago professor of biochemistry and infectious diseases physician Kurt Krause said the new cases in the Waikato were of concern and required careful attention.
"Given that they are almost certainly the Delta variant they will have the capability to rapidly spread within the community. It would be interesting to know if the original case had been tested before moving into the community or not," Krause said.
University of Auckland's School of Population Health professor Rod Jackson said this afternoon's decision to move Auckland to alert level 3 was sensible.
"It was almost word for word what I proposed to the Government."
The people who were becoming infected were those who were "behaving badly" and whether we were in level 4 or 3 wouldn't change that, Jackson said.
He said he hoped the easing in restrictions was enough to make those people who had been breaking the rules more compliant.
"Some people who had gone down to Hamilton to get takeouts will hopefully stop them.
Level 3 was basically level 4 but with takeout, Jackson said.
He said he didn't think any of the country should move down to alert level 1 until enough people were vaccinated.
"The Pfizer vaccine is the champagne of vaccines ... it's the purest vaccine, it's incredibly effective."
"The Government has been cautious all the way through this pandemic ... we have to stamp out this virus otherwise it is going to be smouldering and we are going to be like New South Wales in and out of lockdown," Jackson said.
University of Otago Wellington immunologist Dr Dianne Sika-Paotonu said the decision came with a degree of risk, particularly for Māori and Pacific communities in Aotearoa New Zealand.
"Māori and Pacific peoples remain vulnerable to being disproportionately affected by Covid-19, Sika-Paotonu said.
"It will be important for anyone who is currently unvaccinated to get the Covid-19 vaccine as quickly as possible."
The Prime Minister said director-general of health Ashley Bloomfield was aiming for 90 per cent plus Covid vaccine coverage: "that's the range we want to see people aspiring to. That's the level where we might have fewer restrictions".
Current modelling was to hit the 80 per cent vaccination mark by early October, but he hoped it would get there more quickly, Bloomfield said.
Ardern said the Government remained committed to its "zero-tolerance for cases" approach and was urging Kiwis to follow the rules.
One part of the Waikato, with three new cases, would temporarily move into a "bespoke" set of restrictions.
Ardern said level 4 had helped contain the outbreak in Auckland, and that level 3 still "provided the rules to keep up that containment".
The level 2 rules would be changed, however, to allow a maximum of 100 people to gather, including at hospitality venues, she said.
Ardern reminded Aucklanders that bubbles remained, but said "small" changes to the bubble were allowed to bring in someone who was in lockdown alone, or a caregiver.