There are fears mystery Covid cases in Auckland and the Waikato could be the tip of an iceberg of undetected transmission.
The government is set to announce its decision about Auckland's alert levels today, but it is highly unlikely there will be any change after 50 cases over the weekend, two in Waikato.
Many of last week's cases were found by Janet Masoe-Hundal and her testing team from Pacific health provider The Fono who had spent the weekend door-knocking and testing families in transitional housing.
She was not expecting any alert level change, saying they were still discovering too many cases - and in different parts of Auckland.
"Some of these cases are... mystery cases and can't be linked to any of the clusters so that's the scary part of the work that we do," she said.
Te Rōpū Whakakaupapa Urutā, the National Māori Pandemic Group, was also worried about secretly circulating virus, both in and out of Auckland.
Co-leader Sue Crengle said Covid could stay hidden longer in the relatively young group in this outbreak.
"We remain concerned that there is more going on than simply a long and difficult tail and so we are quite concerned about that - whether there is more circulating Covid in the community," she said.
In the past three weeks there had frequently been cases turning up randomly - at hospitals, in police cells, the surveillance testing of a truck driver who had driven to Palmerston North, and the latest Waikato cases.
Last night, the Ministry of Health announced a parent of a newborn in intensive care at Auckland Hospital was found to have the virus through surveillance testing.
Epidemiologist Michael Baker said the cases suggested a "iceberg phenomenon".
"Where you're just seeing the top of a whole lot of cases ... the tip of the iceberg of cases occurring in the community," he said.
That was more of a problem now Auckland was at level 3 with so many more people working, or moving around - and a worry for the rest of the country with travel across the boundary.
It meant the city should stay at level 3 for at least two more weeks, to try to get vaccination coverage up, he said.
Prime Minister Jacinda Ardern had wanted 90 percent of eligible Aucklanders to have had their first vaccination by today.
That was now at 84 percent, meaning 87,000 more needed a jab to reach the target.
Improving vaccination was one focus for Baker and Crengle and a team of leading public health experts who yesterday called for urgent changes to the government's plan for fighting Covid.
In a University of Otago academic blog, they call for a number of measures including faster and more extensive testing, a moratorium on drug prosecutions and a longer and stronger border around Auckland.
They wanted more mandatory vaccinations, including for people to be allowed into bars, cafes and shows.
Baker said people who went to indoor venues to have fun - laughing, talking, singing and socialising - would want to know the other people there were vaccinated.
"Because if you do those activities indoors and you're not vaccinated you can fill a whole room with an aerosol containing the Covid-19 virus," he said.
The group also wanted more control put into the hands of health providers from Māori and Pacific communities because they were most affected by this outbreak.
The Fono's Janet Masoe-Hundal said people she was testing had often had 10 phone calls from the Ministry of Health or their district health board all asking the same questions by the time she turned up. They were understandably frustrated.
"I would love to just communicate with our families directly and be the one point of contact for them. We understand what they're going through and we have the cultural competency to work with our families," she said.
Te Rōpū Whakakaupapa Urutā is calling for increased routine screening, mandatory vaccination for more groups of workers including healthcare and aged-care staff, an upgraded alert level system, strengthened regional boundaries and more help for marginalised communities.
