The Ministry of Health has reported 80 new community infections of COVID-19 on Sunday, but no further cases in the South Island after one was detected on Saturday.
Most of the infections were in Auckland apart from two in Waikato and one in Northland. The Northland case is linked to previous infections.
There has so far been no further spread from the case reported in Blenheim on Saturday, health officials said, confirming they were unvaccinated.
"Interviews are continuing today with the individual who is a positive COVID-19 case and who is currently in isolation in Blenheim," the Ministry of Health said in a statement on Sunday.
The number of cases in New Zealand's Delta outbreak have now reached 2572. Fifty people are currently in hospital with COVID-19, four of whom are in intensive care.
One of Waikato's cases was reported in Te Awamutu and the other in Hamilton. The ministry said they remain unlinked to the original Auckland outbreak.
"Waikato DHB is continuing to carry out testing throughout the region, to help determine any undetected community spread of COVID-19.
"We are urging anyone in Waikato - in particular, people in Te Awamutu - to get tested if they have any symptoms that could be COVID-19."
The suburb of Redvale on the North Shore is still being singled out due to its high positivity rate of COVID-19 infections.
"We are asking people with symptoms, even if they are mild symptoms, and if they are vaccinated, in Redvale to get tested as soon as possible," the ministry said. "The other suburb where we are encouraging this testing is the North Shore suburb of Rosedale where the positivity rate is 3.8 percent."