There are no new positive cases of Covid-19 in the community today.

There are six new cases in managed isolation, director general of health Ashley Bloomfield says.

Two people from managed isolation facilities are in Auckland hospitals - both are in stable condition.

Bloomfield said he was pretty confident of a "sharp perimeter" around the current outbreak.

"Now is not the time to reassess alert levels but Cabinet is meeting tomorrow on that.

"What we will be looking for over the next 24 to 48 hours is continuing our close contacts remain in isolation.

"I'd like to see tail plus contact, particularly from the gym, those test results coming in, and of course not seeing any other cases pop up from the community. All of this will give us confidence there is no on-going transmission.

"The priority is to make sure we have tied up all loose ends from the college and casual plus contacts from the earlier Kmart exposure, MIT and the gym last week."

Eleven Papatoetoe High School students have had no second test result yet.

Eight were visited yesterday - two had refused tests but were being managed with isolation plans. There is one student the ministry is still actively trying to find.

It was important to get to the last remaining students before making any decision on whether Auckland would change alert levels, Covid Response Minister Chris Hipkins said earlier today.

Bloomfield said the Papatoetoe High School community responded well - "that is hugely helpful and complimentary to any messages we put out publicly".

On students refusing a test: "There is a small number of people who subscribe to the idea that Covid-19 doesn't exist, but they are managed and isolated and made sure there is no risk.

"All 15 cases we have got are in four families. All are contained in Auckland quarantine facility and really we are going back to confirm there's no on-going transmission.

"We just need to be sure there hadn't been seeding of this outbreak outside of Auckland.

"The vast majority of people are doing what they are asked.

"People know what's expected and they do it, and that's how we've been successful."

There are no other "exposure events" for case N - the main one was workplace colleagues and they have all tested negative.

Wastewater test results from ESR have all come back negative, Bloomfield said.

He defended the importance of wastewater testing, saying it provides another level of assurance that there is no community transmission.

On the testing front, there have been 14,671 tests processed with 7853 from across Auckland. The seven-day rolling average of tests is 9721.

Saliva testing

Trials of saliva testing in quarantine facilities are under way, with two or three private providers.

"We had already been looking over the last three weeks, one company is willing, eager and ready to go, but they are not the only one," Bloomfield said.

"Saliva testing still uses PCR lab process, so our current labs. There is quite a lot of work they have on with current testing, so the idea would be if we can get to arrangement with a private provider."

Science for saliva testing has now been validated, Bloomfield said.

"The trial is about acceptability and practicality.

"It's actively under way."

South Auckland a priority

Thirteen DHBs are rolling out immunisation programmes, including all who have an airport, to inoculate the border workforce

So far, two-thirds of the border workforce have had vaccinations.

Bloomfield says he's asked officials to look at prioritising South Auckland in the vaccine rollout"

The majority of the border workforce are based in South Auckland.

"We're putting a layer of protection by vaccinating those workers and their whānau. I've asked the team to start thinking about when we start that wider roll-out, that we first go to the South Auckland community."

Active case N

In terms of active case N, Bloomfield said "we have found many people at the gym but still some with test results pending and some need to remain isolating".

He said 25,000 tests can be processed each day.

"The key things we are looking for are not just the fact we have casual and casual plus contacts ... wider testing provides assurance we don't have wider transmission."

Bloomfield said 45 home visits had been undertaken since Monday - in all visits, people expected to be isolating were doing so.

Of all attendees of CityFitness, 156 returned negative tests, with 29 due for testing.

Of the 44 casual plus contacts from MIT, two returned negative tests. All but two - who were being followed up - had been successfully contacted.

On symptoms

On different symptoms of Covid-19: "Some of the things we see here in NZ, you haven't seen overseas," Bloomfield said. Because the current cluster is made up of mostly young people, they are displaying symptoms that may not have been seen before.

The ministry hasn't rolled out a big vaccination campaign yet because the focus is on vaccinating border workforce and their families, Bloomfield said, but there has been engagement with iwi and Māori leaders.

"We won't be starting the wider vaccination programme until the second half of the year."

On the Tamakis being in Southland, Bloomfield said: "Well he does get around, doesn't he?"

"The request of them has been clear, they should be minimising their interaction with large groups of people."

On the potential damage of Hannah Tamaki saying she won't get the vaccine: "I'm confident we've got a really powerful narrative here, and NZers will take up the opportunity and make decision themselves."

Bloomfield says the information campaign is "the long game".

He has been on Zoom calls with more than 400 Pacific community leaders.

"The wider public information campaign has not gone live, but there is already a lot of information available."

Covid-19 data modelling expert Shaun Hendy this morning told broadcaster Mike Hosking that he believed if there were no new community cases today and tomorrow the Government would likely reduce alert levels.

But even with no new community cases - for four straight days - there is no chance the level 3 restrictions imposed on Auckland will be eased early.

Kiwis will have to wait until after tomorrow's Cabinet meeting before finding out if Auckland will drop out of level 3 and the rest of New Zealand out of level 2 from 6am on Sunday.

Hendy said the UK variant of the virus was challenging to curtail but it appeared shorter, sharper lockdowns to control outbreaks were worth it in the long run.

There was a sting in the tail of the initial outbreak with a three-day lockdown not sufficient to close it out.

"The one thing we know with this B.1.1.7 variant, you really don't want to let it get out of control. It spreads more rapidly and does take a lot of work to control it so my calculus is these shorter, sharper lockdowns to bring these new variants under control is probably worth it in the long run."

He said it was a super-spreading virus so while four out of five people who get infected would only impact household or very close contacts, the fifth person would spread it far and wide.

"It was a good sign yesterday that none of the very large number of tests processed on Tuesday came back positive," Hendy told Hosking.

"That's an excellent sign and we'll be hoping we see the same thing today."

More than 98 per cent of casual plus contacts of "Case A" at Papatoetoe High School have tested negative, after being retested.

A further 33 "close plus" contacts at Kmart Botany, where another of the cluster cases worked, had also returned negative tests, as had 1823 of 1868 people who reported being in the store at times of interest.