Last minute - sometimes random - testing is being done in a handful of areas as the Ministry of Health looks to fill gaps in its Covid-19 data.
Cabinet is due to make a decision on Monday about whether to move the country out of lockdown and needs to know whether the virus is circulating.
Epidemiologists advising the Ministry of Health asked for more testing in Queenstown, parts of Waikato, Auckland and Canterbury.
Waikato has 106 active cases, 71 of them around Matamata, while Waitemata (the north and west of Auckland) had 105.
Hundreds of shoppers were swabbed in Queenstown yesterday in the first major drive to test people without symptoms.
The town has had a relatively high rate of Covid-19, and was home to one of the early clusters - the World Hereford Conference.
- If you have symptoms of the coronavirus, call the NZ Covid-19 Healthline on 0800 358 5453 (+64 9 358 5453 for international SIMs) or call your GP - don't show up at a medical centre
Rural General Practice Network chairperson Fiona Bolden said it was a good move to do the testing there - in part because of its young, mobile population.
"We know that young people are much more likely to be asymptomatic so they may well be carrying coronavirus without having any idea about it," she said.
Southern DHB did not advertise the testing, saying it wanted it to be truly random to help gauge the virus's presence in the community.
In Auckland, two more mobile clinics were due to be launched this week - in west and north Auckland.
A decision was yet to be made about whether there would be random or sentinel testing.
Waikato DHB said it was also planning more testing this week and Canterbury was setting up a mobile service at a marae.
Ministry of Health said it hoped the additional data would help provide information on community transmission in the regions.
Director General of Health Dr Ashley Bloomfield said since the lockdown there were only four cases that have not been able to be traced as either coming from overseas or being connected to someone with Covid-19.
Yesterday's total number of new cases, at 15, was the lowest since level 4 began.
Wairarapa was the only DHB area to have no active cases.
Read more about the Covid-19 coronavirus:
- See all RNZ Covid-19 news
- Covid-19 symptoms: What they are and how they make you feel
- Touching your Face: Why do we do it and how to stop
- Scientific hand-washing advice to avoid infection
- Your Covid-19 questions answered - from health and employment to managing anxiety
- A timeline: How the coronavirus started, spread and stalled life in New Zealand
- Coronavirus: A glossary of terms
- The Coronavirus Podcast