Police are investigating rumours of a dinner party among health workers in northwest Tasmania, where a coronavirus outbreak has shut two hospitals.

The hospitals in Burnie closed on Monday, with a cluster of more than 60 COVID-19 cases, including about 45 staff, associated with the facilities.

Australia's Chief Medical Officer Brendan Murphy revealed rumours of the party on Tuesday morning while he was briefing a select committee of New Zealand MPs about Australia's response to the pandemic.

"We thought we were doing really well in the last week then we had a cluster of 49 cases in a hospital in Tasmania just over the weekend, most of them went to an illegal dinner party of medical workers," he told the committee via video link.

Premier Peter Gutwein told reporters that Professor Murphy was commenting on a rumour but he has asked police to investigate.

"Our contact tracing has not identified a dinner party of health workers. However, I accept that this is a serious allegation, and it's something that needs to be followed up," Mr Gutwein said.

The North West Regional Hospital and North West Private Hospital are undergoing a deep clean by specialist teams after shutting their doors.

Tasmania has called in members of the Australian Defence Force to help progressively get services back online, as well as Australian Medical Assistance Teams.

About 1200 healthcare staff have been ordered to quarantine for two weeks, along with their households, putting up to 5000 people in isolation.

Patients from the two hospitals have been moved to Mersey Community Hospital at Latrobe.

There were six cases statewide on Monday, all in the northwest, bringing the island's total to 150.

Virus testing is also being increased in the outbreak region.

Five elderly people have died from the virus in Tasmania, four of them at the North West Regional Hospital.

People in Australia must stay at least 1.5 metres away from others and gatherings are limited to two people unless you are with your family or household.

If you believe you may have contracted the virus, call your doctor (don’t visit) or contact the national Coronavirus Health Information Hotline on 1800 020 080. If you are struggling to breathe or experiencing a medical emergency, call 000.

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