Prime Minister Jacinda Ardern said that all of New Zealand except Auckland will move to Alert Level 2 at 11:59pm on Tuesday.
Video / Michael Craig / Mark Mitchell / Dean Purcell
But testing rates dropped to the lowest point of the outbreak, and authorities say those numbers need to pick up dramatically to allow a drop in alert levels next week.
Prime Minister Jacinda Ardern announced yesterday what she called "Delta level 2" for the country outside Auckland's borders, to keep up with the more-infectious variant that had "changed the game".
This means masks in many indoor venues and smaller limits on gatherings, along with other measures to reduce the risk of any community transmission.
Mask use in schools will be "highly recommended" but not compulsory.
The alert level move came off the back of three days of cases hovering around 20 daily - well down on the peak of 84 just over a week ago.
There are now 821 cases in the outbreak, including 804 in Auckland and 17 in Wellington.
Epidemiologist Michael Baker told TVNZ Breakfast today he hoped level 2 was "short term" and the country could get back to level 1.
He and other researchers had called for a more stepped level system which would allow for some looser restrictions at the lower levels.
Prime Minister Jacinda Ardern. Photo / Robert Kitchin
Auckland could potentially move down levels while there were still new cases arising, as long as they were contacts of known cases, he said.
Chris Hipkins told Newstalk ZB that he was "optimistic" about yesterday's announcements and overall the numbers were pointing in the right direction.
Asked about mystery cases, Hipkins said he didn't necessarily need to know where every single one came from but if they were still seeing a high number of mystery cases each day then that would be a concern.
Hipkins said we could expect to see more saliva testing as health advice changed.
As for South Island going to level 1, Hipkins said the Government wanted to see Delta contained.
"There's still a lot of movement across that land border.. there's still risk there. But I'm quite optimistic that it's coming back into containment again."
Ardern told the AM show there would be news on future vaccine supplies by Friday.
When asked to comment on ACT leader David Seymour's tweet in which he shared the access code for Māori, she said it was "wrong".
Ardern confirmed the wage subsidy was still available if any part of the country was at level 4 and 3 - even if the business applying was itself in level 2.
She told TVNZ Breakfast that Aucklanders were carrying a huge burden for the rest of the country.
An abandoned Fort Street as Auckland remains in Covid-19 alert level 4. Photo / Dean Purcell.
She urged everyone who was symptomatic to get tested and for everyone to stick to a tight bubble.
Please keep following the rules, she said. "You don't want to have to ...fess up that you've been mixing and mingling with other households."
Baker told Newshub it should be mandatory for high school students to wear masks when school resumes on Thursday.
Teenagers was an age group where Delta had proved highly transmissible internationally.
The outbreak situation was looking very optimistic at the moment and the virus could be eliminated from New Zealand.
He said after a period of adjustment it may see New Zealand land on a revised level 1.
Level 1 would look looser, but warned it may not have quite the same freedoms as the past 18 months, he told Newshub.
Baker wasn't "absolutely certain" Auckland would move out of level 4 next week. He said while case numbers were dropping, it was the mystery cases that were concerning.
"If there's no virus in New Zealand then we can be a bit freer."
Waste water testing could also help confirm that and didn't rely on everyone doing the right thing and being tested. It was still important for people to get tested because it told them where the virus was, whereas waste water testing just confirmed it was in the community, Baker said.
PM's concern at mystery cases
The low daily case numbers give cause for optimism, however Ardern said they were still concerned about the prevalence of mystery cases, those not yet linked to other cases, of which there were now 33. At the peak of the outbreak the numbers were around 60.
These numbers would need to be slashed even further ahead of any changes to alert levels come Cabinet's alert level decisions next Monday.
The number of tests has also fallen dramatically, with just 2088 in Auckland on Sunday and 4750 across the whole country - well down from the daily average of over 20,000 at the peak of the outbreak.
This was largely due to fewer new locations of interest and the lockdown's impact on the spread of respiratory illnesses.
Director general of health Dr Ashley Bloomfield said those rates needed to boost up again ahead of any alert level change in the city, urging anyone with symptoms to get tested.
"The big focus is on Auckland and making sure we do everything we can to support efforts there and get confidence the outbreak is well controlled there."
Consequently the Ministry of Health would be stepping up surveillance testing in healthcare, border, quarantine and essential workers. It was also introducing more saliva testing locations.
"Delta level 2" includes many of the old measures, with just a few tighter restrictions.
Schools outside Auckland will be able to operate once again from Thursday.
Face masks must be worn inside most public venues, including shops, malls, and public spaces, but could be removed for eating and drinking.
Masks would not be compulsory at schools, nor universities, but Bloomfield said they were "highly recommended".
New rules on scanning also applied at level 2 - mandatory scanning at bars, restaurants, cinemas, churches, hairdressers and anywhere where there was close contact between people.
As well, there will be a limit of 50 people at hospitality and event venues, while outdoor venues can have up to 100 people.
Distancing requirements had increased from one to two metres, meaning venues not captured by the crowd limits would also have reduced capacity at level 2.
The alert level change has been welcomed by experts, with most calling for a level 2 shift ahead of the announcement.
Otago University's Professor Nick Wilson said that, along with keeping places like pubs, restaurants, gyms and churches shut at level 2, the Government could have imposed more comprehensive indoor mask requirements.
