Aucklanders fleeing the city for the school holidays are being urged to take their alert level restrictions with them.
The exodus of Aucklanders comes as scientists say the newest Covid cluster has the potential to be very serious.
Having stemmed from a rare Covid case which emerged after the person had left managed isolation, it could also force officials to rethink how long people are kept in isolation, one expert said.
It is the first weekend since Auckland moved to alert level 2 and the rest of the country shifted to level 1.
Director general of health Ashley Bloomfield said Aucklanders should still behave as if they were in alert level 2 even if they were outside the city.
"Even as we go into the school holidays … a reminder to Aucklanders – great they will be travelling around the country, and it's good we're in a position they can do that - just to be mindful," he told RNZ.
There were two new Covid cases confirmed yesterday
, one a traveller from overseas and the other in the community - a young woman who was already in isolation.
Public health services are tracking close contacts of a new cluster which currently has six positive cases.
It is believed to have started with a man in his 40s who returned to New Zealand from India on September 11. He spent 14 days in managed isolation in Christchurch, and flew home to Auckland on a chartered flight.
He then tested positive, and is believed to have contracted Covid-19 after a rare 21-day incubation period.
"The advice to anyone – and this is how we've got on top of this – late last week a fellow from the flight, even though he had been right through managed isolation and tested negative twice, he developed symptoms, self-isolated and got tested," Bloomfield told RNZ.
"So my plea is, for anyone around the country, if you do develop symptoms, do isolate, stay at home and get tested. That's how we will keep ahead of this virus."
Two people who were on the same chartered flight from Christchurch also tested positive, along with a household contact. The three infected people went to Taupō (before discovering they were infected) and met with a group of 18 others last weekend.
Bloomfield said that was "not ideal" because the maximum gathering size for Aucklanders was still 10 at the time. But the families had carefully used the contact tracer app which had made it easier for public health officials to track their movements easily.
The five families who travelled to Taupō came from all corners of New Zealand, including Kawerau, Wellington, Auckland, Hamilton and Christchurch.
After officials discovered that two of the group were on the chartered flight from Christchurch, they contacted the family. The family went into isolation when they returned to Auckland and tested positive.
There are now 35 close contacts associated with the Taupō group. Of those, eight have returned negative test results and the rest have been or are in the process of being tested. All of them are in isolation.
So far 15 eateries, shops and tourist attractions had been marked by the Health Ministry as locations of interest between Auckland and Tūrangi.
Epidemiologist Professor Sir David Skegg said the newest cluster had the potential to be very serious.
"This is just a reminder that elimination is a process, not a destination.
"This will keep happening and it's essential we can keep on top of the cases."
Covid-19 modeller Shaun Hendy said the advice on isolation duration needed to be adjusted as more was learned about the disease and its possible incubation period.
"There should be some concern about this latest case and I think particularly because it is distributed across the country, it's not confined to one part of the country."
Bloomfield said health officials were investigating where the latest cluster came from.
It was not known whether the man caught the virus in Delhi, India, where he flew from, within the managed isolation facility in Christchurch, or on the chartered flight.
Genome sequencing would identify whether he or two other family members on the flight were infected first.