Health bosses yesterday revealed dozens more positive Delta cases could emerge over the coming days.
The warning comes as the Government prepares to decide if it will change the Auckland region's current level 3 regulations; with more than one Covid-19 expert saying dropping to level 2 would be a "big jump".
New Zealand has also been told to forget about a return to pre-Delta freedoms, with director-general of health Ashley Bloomfield saying the future will look different.
Masking up, scanning in and a vaccine pass to enter some venues will be part of life as long as the Delta virus remains, Bloomfield has told Newsroom.
The health boss also said he remained committed to elimination, even as cases hover in the double digits.
Fronting Friday's 1pm update, director of public health Dr Caroline McElnay said 35 more new cases could be expected in the coming days among household contacts, together with some fluctuation in daily case numbers because of just how infectious Delta is.
Many clusters were now contained but five active sub-clusters remained, said McElnay, who fronted the 1pm update with Deputy Prime Minister Grant Robertson.
All but one of Friday's new cases are linked, bringing a total of nine unlinked cases from the past two weeks.
Robertson said it was encouraging that most cases were linked, and case numbers had been relatively stable.
"But we must not be complacent," he said, urging people in Auckland to get tested.
"We saw 19,000 tests across New Zealand and that's an excellent number, and we want to keep that level of testing up over the weekend."
Getting enough tests to be able to derive an accurate picture of whether the outbreak is contained is one factor the Cabinet would consider in its alert level decision on Monday, he said.
McElnay said there was broad-based surveillance testing in place targeting suburbs of concern.
The plan ensured a good representative sample of Auckland, and changed according to where new cases emerged.
Unlinked cases allowed authorities to "go on a hunt" to find where other cases might be, she said, which could mean daily tweaks of surveillance testing.
Robertson said the reality was that bubbles were mixing, but it's not a "hosting of parties"-type approach, but larger family groups interacting on a minimal basis like delivering a food parcel, which can lead to transmission from time to time.
Prime Minister Jacinda Ardern has said it was likely Auckland's boundary will remain in place even if the region moves to alert level 2 next week.
Leading Covid-19 modellers and experts say even that won't be enough to safely loosen restrictions on the city.
University of Canterbury Professor Michael Plank says dropping from level 3 to 2 is a big jump and likely to cause an increase in case numbers, which modelling shows will lead to more hospitalisations and deaths.
"We're only now getting a clearer picture of what level 3 is doing and it's a struggle to contain the outbreak," said Plank, the principal investigator at Te Pūnaha Matatini.
Associate Dean Pacific at the University of Auckland Collin Tukuitonga says case numbers hovering around the 20s is a worrying sign.
Asked about an earlier suggestion for an alert level boundary around key suburbs like South Auckland, he said it seems like a good idea but "not very feasible".
"People may feel discriminated against," he said.
The next few days will be crucial in terms of case numbers, says Professor of Public Health at University of Otago Michael Baker.
"What we've been doing has not been enough. We're into week seven now, the first two weeks went really well at stamping out most transmission chains, then we've had this very stubborn chain for four weeks."
He says a "review and refresh" of the Government's existing strategy is needed.
Covid-19 has affected people in difficult situations - in marginal housing, with alcohol and drug problems, and with gang connections - groups who require "very intensive work to engage with effectively", he said.
He believes the country will be in a better position to decide on dropping levels next Friday at the earliest.
"Even if it doesn't work, we are buying time, we are learning about how to keep a lid on the virus while we get our vaccinations up, and while we get all of our other systems in place to manage a lot more sick people in primary care and hospital systems, a lot of useful things we can do even if we can't quite manage to stamp it out."
Hospitals the 'solution, not a problem'
On recent exposure events at Middlemore Hospital, McElnay said Covid-positive patients there were not unusual because of existing sub-clusters in South Auckland.
She said Auckland hospitals were used to dealing with Covid patients and clinical staff were "doing an excellent job".
But there had been reports of physical violence and abuse against essential workers, and she called on New Zealanders to be kind and treat staff with respect.
Robertson said some people were arriving at Middlemore completely unaware they had the virus, some of them were quite unwell and had to be admitted.
There were cases where testing did not occur, Robertson said, but it was not a problem at the hospitals; rather, they were the solution.
"We do also really want to make sure people retain confidence in our hospitals", Robertson said "and it's important they still go there if they are unwell."