Air New Zealand is refusing to say whether any crew members who arrived on an international flight with an infected flight attendant have since traveled home to other parts of the country.
The airline staffer who tested positive at the weekend arrived on a flight from Japan on February 28 and received their vaccination on March 3. She is at the centre of Auckland's newest border-related case.
"Given the small number of air crew involved, we cannot disclose their residential areas in order to protect their privacy," an Air NZ spokeswoman said.
"They are all following the Ministry of Health advice on isolation and testing."
This latest case is now one of up to three airline staff to have become infected in recent months. The other two were people who had worked on flights from Shanghai and Los Angeles.
The spokeswoman said all passengers who arrived on the Tokyo flight on February 28 have gone into MIQ as per normal entry requirements.
However crew were not required to go into isolation as the flight was not considered "high risk".
Prime Minister Jacinda Ardern told TVNZ's Breakfast health officials were assessing whether more restrictions were needed on international crew, depending on what location they're coming from, given the latest case.
"As circumstances change in different places [countries], we look at whether or not we need to be heightening what we're doing."
The crew member had tested positive during routine surveillance testing on Saturday, and had received the vaccination three days after arriving home.
Ardern said the crew member was one of more than 9000 border, managed isolation and quarantine staff to have already been vaccinated against the virus, but the jab hadn't had time to take effect.
"This person had only just been vaccinated, so they were a priority for this exact reason," she said.
"The issue being, of course, that the vaccine takes a couple of weeks to work so at this point it wasn't quite doing its job and nor would we have expected it to, but it does demonstrate this person was indeed a priority for us."
Health authorities are now working to identify the strain's genome sequence.
Leading epidemiologist Michael Baker is calling on officials to review current rules around airline staff not having to quarantine after arriving from overseas.
"Perhaps we need to review the process we're using for aircrew just to make sure we think it's sufficient to keep New Zealand safe over the next few months," he told Newstalk ZB.
Under the current rules, New Zealand-based international aircrew are mostly exempt from the 14-day managed isolation period other people arriving from overseas currently must undergo.
However, airline staff must undergo a normal health assessment on arrival.
Baker said the fact the staff member had been picked up with a routine test was good news but he acknowledged the lack of isolation on arrival of airline staff was worrying.
"Throughout the pandemic, it's always been a source of concern - the fact that we have a very different process for air crew.
"They have never gone through the standard process that other returning travellers do - which is ...14 days in MIQ and two or even three tests now.
"There have been reasons for that. But it's obviously an area of vulnerability."
The latest case also visited the Countdown Auckland Airport, on the corner of George Bolt Memorial Drive and John Goulter Drive in Māngere, last Wednesday afternoon.
Anyone who was in the supermarket - now a location of interest - between 12.07pm and 1.22pm on that day is regarded as a casual contact and is asked to monitor their health until March 17.