The new Auckland coronavirus outbreak has grown to 13, including three staffers at a warehouse and a student.
The Americold warehouse employees worked with a man in his 50s who tested positive for the virus on Tuesday alongside three family members.
The 13 new cases in Auckland are from community transmission, while another woman, a returned overseas traveller, has also tested positive.
There are now 36 active COVID cases in the country. All are going into, or are already in, mandatory hotel isolation.
Prime Minister Jacinda Ardern said during a press conference on Thursday that the number of infections is expected to grow.
“As we all learnt from our first experience with COVID, once you identify a cluster, it grows before it slows. We should expect that to be the case here,” she said.
One of the new cases confirmed on Thursday is a student at Mount Albert Grammar, the country's second-largest school with 3000 pupils.
The student attended class on Monday, and local health authorities said they were contacting and isolating around 100 close contacts they had while at school.
There are also four new cases of employees at two Auckland businesses and eight family members of those employees, all linked to the index case.
Director-General of Health Ashley Boomfield also announced on Thursday one more probable case.
Ms Ardern said the cluster of cases was "serious but being dealt with in urgent but calm and methodological way".
Auckland residents were placed into a 60-hour stage three lockdown from midday on Wednesday after the shock announcement a family of four were infectious earlier this week.
It was revealed one of the family members worked at the Americold plant, while a second is linked to a finance company.
Americold Managing Director of Australia and NZ, Richard Winnall, said all warehouse staff are now isolating, according to NZ Herald.
"It's not good. There's a lot of people awaiting test results, they've got families. There's a lot of anxiety and concern," he said.
Almost half of the staffers have already received their results back.
"At the Mt Wellington facility we've had a further three confirmed cases. They were earmarked as close contacts and probable and they've all come back as confirmed," he told the publication.
New Zealand officials are investigating if infected refrigerated goods led to the family’s infections.
Mr Winnall said there had been an outbreak at the company’s Melbourne facility, but insisted the virus hotspot was not connected to the Auckland outbreak.
He said there were no shipments between the two.
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