It is "highly unlikely" that a breach in New Zealand's managed isolation and quarantine system (MIQ) is the source of Auckland's three new community cases, says Prime Minister Jacinda Ardern - however, a transit passenger or international airline crew are possibilities.
On Sunday, it was announced that three new cases of COVID-19 - a mother, father and child in the same South Auckland household - had been detected in the community.
It was later confirmed that Auckland would transition to level 3 lockdown at 11:59pm on Monday for a 72-hour period - a "cautious approach" that was the right decision, Ardern said.
Genome sequencing confirmed the three people are infected with a mutated strain of the virus, B.1.1.7 - also known as the UK variant. It's understood that the variant is more infectious than the strain that first circulated New Zealand last year.
However, sequencing was unable to link the initial infection - a worker at the Auckland Airport branch of LSG Sky Chefs, a flight catering facility - with any of the cases currently in the MIQ system. How exactly the employee contracted the virus remains unknown.
Speaking to The AM Show on Monday morning, Ardern said it's "highly unlikely" the first case was infected due to a breach in New Zealand's MIQ system.
"It [does] give us a couple of scenarios that we need to chase down," she said.
An infected transit passenger who failed to remain airside at Auckland Airport is one possibility that health officials are considering, Ardern revealed.
"It could be, for instance, a situation where a transit passenger has been the source of infection - they're required to stay airside," she explained.
"But of course, we have airside workers - and they will have used the blankets on international flights that then go through the laundry at the [case's] place of work."
The case may have also contracted the virus by handling clothes worn by an infected international airline worker, Ardern said.
"International airline crew do in some cases have their uniforms washed at the [case's] place of work."
Health officials are now attempting to find a match with the initial infection, the Prime Minister said. Airlines are currently being contacted to see if a link can be established between the first case and an infected crew member.
"We do have the ability to go through and see if we can data match by contacting colleagues in places where they have got transit passengers in managed isolation. We will be, and we are, contacting airlines to see if they have a match to their crew."
Ardern also reiterated the importance of testing at LSG Sky Chefs to ensure the virus was not transmitted to the coworkers of the initial case.
The Prime Minister and Director-General of Health, Dr Ashley Bloomfield, will provide the latest updates on the new cases in a post-Cabinet press conference at 4pm.