Household and close contacts of the Auckland Airport worker who tested positive for COVID-19 on Tuesday have so far all returned negative results, it has been revealed.
Genome sequencing finished on Tuesday night showed the worker highly likely picked up their infection from a passenger who'd travelled to New Zealand from Ethiopia on a plane they later cleaned on Saturday, April 10.
No new cases of coronavirus were detected in the community over the last 24 hours, and just one was recorded in New Zealand's managed isolation and quarantine (MIQ) facilities.
The new information was revealed during a press conference from Parliament fronted by COVID-19 Response Minister Chris Hipkins and Director of Public Health Dr Caroline McElnay on Wednesday afternoon.
Dr McElnay revealed health officials had identified 25 close contacts of the airport worker to date - seven of whom have returned negative results.
"One is being followed up today, and the remainder of those identified are not yet due for testing," a Ministry of Health statement reads.
"This is because we test close contacts on day five after they have potentially been exposed to the virus for the best chance of detecting any infection that may be incubating. All close contacts are self-isolating.
"Of those, 17 are workplace contacts. This number will likely increase - the person worked three shifts during their infectious period with a number of colleagues, and officials are working to determine who is a close contact from their interactions."
The ministry says the results from whole genome sequencing of the worker's PCR test was indistinguishable from that of a person who arrived in the country on April 10 from Ethiopia via the United Arab Emirates.
"The genome of both these cases is the B.1.1.7 - which is the variant first identified in the UK," it said.
The worker cleaned the same plane the passenger arrived on, but despite the clear link between them a full investigation of how the cleaner was infected is being carried out.
Dr McElnay said the new MIQ case arrived in New Zealand on April 16 from Switzerland, via Qatar, and tested positive on day three of their routine testing regime.
The number of active cases in New Zealand falls to 83, after five previously reported cases recovered on Wednesday.
The total number of confirmed cases is 2243.