A neighbour who lives in the same apartment building as the Auckland student with Covid-19 has returned a "weak positive" test for coronavirus.
"This individual lived in a neighbouring apartment in Vincent St apartments to [the student]," the Ministry of Health said today.
The person was already in a quarantine facility, the ministry said.
"The individual's initial test result was negative, but a subsequent test has today returned a weak positive result. A further test is now being taken. They are currently regarded as a case under investigation."
There are three other Covid-19 cases today in managed isolation.
One recent arrival from Romania landed in New Zealand on November 3 via Qatar and Australia. They tested positive at around day 12 routine testing and are now in the Auckland quarantine facility.
The second case arrived from Australia on November 1 and was also detected on testing around day 12. This person has now also transferred to the Auckland quarantine facility.
The third case arrived from the UK on November 12 and tested positive on arrival and transferred to Auckland's quarantine facility.
One previously reported case has now recovered, meaning the total number of active cases remains at 56.
The total number of confirmed cases is now 1643.
Yesterday, laboratories completed 6320 tests for Covid-19, bringing the total number of tests completed to date to 1,169,062.
Covid poster scans have reached 114,559,362 and there have been 4,767,798 manual diary entries.
"Over a million scans took place yesterday, the most since 1 October, which means around one in five app users were scanning the codes," the ministry said, which was "encouraging".
Testing sites have been busy across Auckland today, after the CBD was yesterday shifted out of its quasi-lockdown after genomic testing proved the AUT student was infected by the Defence Force serviceman from the quarantine cluster.
The genomes from Case A - the serviceman who caught the virus in the Jetpark quarantine facility - and Case D - the AUT student - were identical, which is consistent with direct transmission between the two.
That doesn't exclude the possibility of someone else being in the chain, but officials are confident the time-frame suggests there was not a long chain of transmission involving a lot of people.
There were no other positive cases of Covid-19 in the community yesterday despite more than 7200 tests being processed, including more than 100 from the woman's Vincent Residences apartment building.
How the AUT student was infected is still a missing piece of the puzzle.
She works just 82m from a cafe the defence worker visited, but extensive interviews haven't uncovered an obvious connection.
Despite confidence the cluster is well-contained and widespread transmission is highly unlikely, Covid-19 Response Minister Chris Hipkins will move next week to make masks mandatory on planes and on public transport in Auckland.
The public health order is being drafted and will be presented to Cabinet on Monday with the support of the Prime Minister.
Confusion over sick leave claim
Auckland Regional Public Health Service (ARPHS) has been responsible for contact tracing interviews with the woman, who is aged in her 20s and who works at A-Z Collections on High St.
On Thursday, director of public health Dr Caroline McElnay jointly fronted a press conference with Hipkins, and said the woman called in sick to work after being tested, but ended up working after talking to her manager, but wore a mask.
However, A-Z Collections owners, husband and wife Bing Wang and Mei Chen, have since issued a statement via their lawyers, Focus Law, claiming the employee had never told them she was sick, sought to call in sick, or that she'd had a Covid test.
The Herald has been unable to speak to the student directly. Focus Law released a statement from her, saying on the evening of Monday, November 9 she had a sore throat, and contacted her GP the next day, and they recommended a Covid test.
On Wednesday, November 11, her sore throat had gone, the statement read, and she went to work, wearing a mask "just to be safe".
"I did not tell my boss or manager of the above and did not request leave at any time. I did not think it was a big deal."
According to the statement, language barrier issues meant ARPHS staff "made many errors in recording my previous whereabouts, actions and contacts".
Yesterday, officials arranged for a translator to assist contact tracers.