New Zealand authorities are investigating whether a recent outbreak of COVID-19 in the community came from chilled products shipped from overseas.

Particular focus is being concentrated on a Melbourne cool store where two workers recently tested positive for the disease.

As investigations into the outbreak continue, Director-General of Health Ashley Bloomfield said he has been speaking to his counterpart in Victoria, where a company linked with the New Zealand outbreak also has facilities.

Genome testing was underway on employees in Melbourne to see if there were any connections.

“We’re looking at that possibility, it’s part of the overall puzzle and we are leaving no stone unturned,” Dr Bloomfield said.

Further test results from the New Zealand sites are expected later on Saturday, Dr Bloomfield said.

New Zealand has reported seven cases of the new coronavirus for the past 24 hours as a lockdown in the country’s biggest city, Auckland, was extended in response to the country’s first coronavirus outbreak in months.

The country has recorded 37 coronavirus cases spread within the community and 19 cases from travellers in hotel quarantine.

The developments come after more than 100 days of zero community transmission.

Six of the seven new cases reported on Saturday have been linked to the cluster responsible for all the previous community cases, Dr Bloomfield told a media briefing in Wellington.

Prime Minister Jacinda Ardern on Friday announced lockdowns across the country would remain in place until August 26.

Prime Minister Jacinda Ardern has announced New Zealand’s current restrictions will remain in place until August 26. Photo: Getty

Health Minister Chris Hipkins said contact tracing across the country had been going very well.

He urged people to maintain social distancing and “follow the rules” as they went about their lives.

“We all want to be out of level 3 as quickly as we can and people following the rules is the best way out of that,” he said.

Dr Bloomfield said a strong testing program was one of the reasons behind New Zealand’s success in fighting the virus.

He conceded he would have liked it to have started faster than it had, while denying there had been other major problems with the scheme.

A new strain of the virus has emerged recently and Dr Bloomfield said it was more of a “variation on a theme” and there was nothing to suggest is was more infectious or severe.

-with agencies