Prime Minister Jacinda Ardern wants advice from health officials on extra measures for travellers after completing managed isolation amid a fresh Covid-19 outbreak detected in an adult and child.

Ardern said "something had happened", resulting in the virus being spread among guests at the Pullman Hotel isolation facility. As a result no new returnees were coming into the Pullman while the situation was being investigated.

Asked if new rules could be put in place to prevent returnees leaving their rooms at MIQ facilities, Ardern said there were protocols in place for people who were getting fresh air.

"If they need to be tightened because of what we find in this, we will do it," she said.

Officials were looking at whether guests should stay in their rooms at the tail-end of their stay while they wait for test results, like they do at the start of their stay.

"We have allowed people to get fresh air [because] they are in small confined spaces we are mindful the fact that the vast majority of people do not have Covid in these facilities and just enabling people to get through their two weeks but in the safest way possible, that's the balancing act," she said.

Prime Minister Jacinda Ardern speaking to reporters in Auckland today.

Ardern said she was confident in New Zealand's systems and said that Australia's decision to suspend quarantine-free travel was up to its officials.

Asked about further safeguards at MIQ facilities, Ardern said the new cases were still linked to the border.

New rules have come into place since the further positive tests and would make a difference, she said.

"It is clear due to the link to these cases that something had happened," she said.

Further investigations were underway to understand how the infection had taken place at the Pullman Hotel.

"We've had tens of thousands of people successfully move through but we're looking at further assurances," Ardern said.

She is getting advice from health officials on what extra measures should be put in place when people leave MIQ, such as more testing or rules for recently released returnees.

Health officials moved quickly, she said, to reach those in the Pullman Hotel and she was seeking more information on why it has taken longer for some to get tested.

There were issues locating a small number of people, she said.

Asked if she could rule out further results in the community, Ardern didn't directly answer the question.

She was waiting for further test results to come through.

Asked how the infection happened, she said nothing was being ruled out and that it could be surface-to-surface transfer, transfer via the air or people simply passing each other.

"The people who work in managed isolation facilities are heroes," the Prime Minister said when asked if staff at those centres need to pick up their game.

Asked if there was too much contact at the Pullman Hotel between returnees, Ardern said officials were being rigorous at working out what had happened.

"They are being kept in their rooms while we work through this issue," she said.

No new returnees were coming into the Pullman Hotel while the situation was being investigated.

Concern for Auckland events

Auckland Mayor Phil Goff is signalling major events may be canned to prevent a large-scale coronavirus outbreak as people flock to testing stations, concerned they have been exposed to the contagious South African Covid strain.

As the City of Sails gears up for one of the biggest weekends this year, the prospect of a community outbreak after two months looms large, with two new cases in people who completed their managed isolation in Auckland's Pullman hotel at the same time as a Northland woman two weeks ago.

Earlier today Covid Response Minister Chris Hipkins revealed a child and adult from the same family were the latest to succumb to a highly contagious Covid variant, becoming the second and third official cases connected to the latest Northland community outbreak.

It makes them the second set of returnees to walk out of managed isolation at the five-star hotel with an undetected infection in the past fortnight after the 56-year-old Northlander tested positive for Covid nine days after leaving managed isolation on January 13.

The latest community cases were detected when health authorities asked all 354 people who had stayed in the facility between January 9-24 to get re-tested.

There are lengthy queues at the Albany Covid testing centre this morning. Photo / Hayden Woodward

While health authorities impose a raft of restrictions on the hotel, including keeping the present contingent of returnees on the premises until they know how the infection spread, the city's mayor Phil Goff said Aucklanders needed to be on alert.

While there was no widespread evidence of community transmission, the system needed to err on the side of caution and "if necessary we may need to close down events".

"At this stage it's not deemed necessary according to the health authorities and it's important that we follow that expert advice," he said.

While he hoped it wouldn't amount to anything greater, he urged people to be extra vigilant.

Auckland is gearing up for a big three-day holiday weekend, with the semifinals of the Prada Cup, Seeport Concert and Fireworks, and the annual anniversary-day regatta.

Worried Aucklanders form long queues at an Albany testing station as two new cases emerge in the Northland community outbreak. Photo / Hayden Woodward

"We've had two months with no community transmission but the system isn't failsafe. This is further evidence of that," said Goff.

More testing stations had been set up overnight, staff had been drafted in and hours had been extended, he said.

"I do urge health authorities to make sure the resources are in place. We don't want to see the sort of situation that existed for a short period in the north where people had to wait hours for testing," he said.

It comes as health authorities confirm the infected returnees spent an hour from midday at the Farmer's department store in Albany's Westfield mall on Sunday.

Silverdale Pak'nSave supermarket where the two infected people visited twice on January 17 and 18, was today open for business.

In a Facebook post the store's owners said while public health considered the risk to be relatively low, front of house staff when the positive cases visited were isolating at home and would take a test, returning to work only when they have a negative result.

Big queues were quickly forming at Covid testing centres as worried Aucklanders who had been at any one of the dozen restaurants, supermarkets, shops and petrol stations visited by members of the infected family sought tests.

One man, who had moved just 200m in 90 minutes at an Orewa pop-up station, described the situation as deteriorating the longer people waited.

"It's getting pretty ugly here," he said.

This morning, Hipkins said while it was unlikely there would be a change in alert levels "everything is always under review".

He said genome testing had shown the pair were linked to the first infection at the Pullman Hotel.

That meant they had potentially come into contact with the returnee with the South African strain while staying in quarantine.

There were currently six close contacts associated with the family bubble that were initially isolating in their Orewa home.

All had returned negative tests.

The infected pair had since transferred to Auckland's Jet Park quarantine facility. Last night they were described as asymptomatic.

Extensive testing was now under way for all returnees that had left the Pullman. Around 300 people had already tested negative. Another 54 people were still to be tested.

"There does appear to be something at the Pullman Hotel and we're looking very closely to identify what it was there," said Hipkins.

"The Pullman hotel will empty out a little bit. We're not letting anyone leave the Pullman hotel at this point until we're absolutely certain we've contained whatever the risk is."

The director general of health Dr Ashley Bloomfield said a number of measures were being imposed as a result of the infection breach.

It included a deep clean of commonly used areas, tighter restrictions on movement of returnees including no arrivals or departures from the facility, and increasing hotel ventilation.

The Ministry of Health was also requesting returnees who had recently left, to not fly, to stay home and have an additional test within 48 hours.

Staff posted at the facility were being restricted from working at other sites.

Further north, the self-appointed Tai Tokerau Border control team was setting up at Waiomio on SH1, just south of Kawakawa.

Spokesman Hone Harawira said private vehicles heading north would be handed flyers that contained information about Covid, including the location of regional testing stations.

Checkpoints were also being set up in Kaikohe and Dargaville.