Prime Minister Jacinda Ardern has confirmed New Zealand south of Auckland will move to alert level 3 from 11.59pm tomorrow night.
Level 3 would be in place for a week before it was reviewed, Ardern said.
Business owners and operators who ran businesses allowed to operate at level 3 were able to return to their workplaces to set-up for operating at the reduced alert level.
There had been no evidence that would cause Cabinet to change its mind, she said.
"Wider waste water testing in Christchurch has not shown up any further postive results meaning the positive results last week we believe can be most likely attibuted to cases in managed isolation facilities in the city."
Auckland will stay in alert level 4 for at least two more weeks - until Tuesday September 14, Ardern confirmed.
Wastewater testing in Northland is due on Thursday. If the tests are all clear, Northland will go to level three at 11:59pm on Thursday.
Ardern reinforced to New Zealanders outside of Auckland to remain cautious.
"My final message is for all of those outside of Auckland. Please remember that level 3 does not mean freedom.
"It means caution, it means staying in your bubble, it means distance, it means contactless transactions."
Ardern said this afternoon that today's numbers showed level four was making a difference, with cases decreasing outside of households.
But, she said, "we need to be confident any cases we may have are contained and isolated".
Everyone in Auckland knows we are not there yet, Ardern said.
The PM presented a graph which indicated what would have happened if we hadn't moved quickly into lockdown, with cases "literally off the charts", totalling 550 per day.
"The more we do to limit our contact, the faster we exit these restrictions."
Ardern cited evidence offshore where countries were battling large hospitalisation rates.
53 new community cases
It comes as 53 cases, all in Auckland, were announced on Monday. After highs of 82 and 83 in the preceding days, the drop is the strongest indication yet the lockdown in place since August 18 is having an impact.
Director-General of Health Dr Ashley Bloomfield described today's data as encouraging.
He said of yesterday's 83 cases, 72 per cent didn't create any new exposure events. Of yesterday's cases, only 28 per cent were considered to be infectious in the community.
Bloomfield said the R value was now under 1, which was a good sign.
One hundred and one essential workers were cases, but many were from earlier in the outbreak, Bloomfield said. Four were infectious in their workplace and seven had been infected in their workplace.
Thirty-seven cases are now in hospital. Of those, five cases are in stable condition in the intensive care unit.
Close to 47,900 Covid vaccines were administered yesterday - a record for a Sunday. Over 50 per cent of the eligible population has received at least one vaccine dose.
Of the 3.33 million doses of the vaccine administered to date, 2.17 million are first doses and 1.16 million are second doses.
There are now 79 confirmed cases in the Birkdale Social Network cluster and 280 in the Māngere church cluster.
The ministry said ESR has run whole genome sequencing on samples taken from about 345 community cases. Analysis shows they are all genomically linked to the current outbreak.
The drop in cases from the weekend – when over 80 new cases were recorded on both Saturday and Sunday – is a welcome sign as Cabinet prepares to meet to confirm the extension of level 4 for Auckland and Northland from 11.59pm Tuesday.
Most of the new cases will be from tests on Saturday, when 23,000 people were swabbed for Covid-19.
Yesterday 16,370 tests were processed across New Zealand. That was lower than the 36,000 tests on Thursday and 37,000 on Friday.
Meanwhile, a woman has died after developing myocarditis, a rare side effect of the Pfizer Covid vaccine.
The Ministry of Health said this was the first case in New Zealand where a death in the days following vaccination has been linked to the Pfizer vaccine.
The Ministry says the Covid-19 Vaccine Independent Safety Monitoring Board advised officials to ensure that healthcare professionals and consumers remained vigilant and were aware of the signs of myocarditis and pericarditis following her death.
"The CV-ISMB considered that the myocarditis was probably due to vaccination. The CV-ISMB noted that there were other medical issues occurring at the same time which may have influenced the outcome following vaccination," said the Ministry in a statement.
The woman's death had been referred to the Coroner and the cause of death had not yet been determined, said the Ministry.
While the Centre for Adverse Reactions Monitoring had received other reports of deaths in someone recently vaccinated, none were considered related to vaccination.
The Ministry said the benefits of vaccination using the Pfizer brand continued to greatly outweigh the risk of both Covid infection and vaccine side effects, including myocarditis.
