A man in his 50s is among the latest casualties, with Victoria recording 403 new cases and Australia's death toll rising to 133.

Treasurer Josh Frydenberg revealed the economic cost of the public health crisis in a special budget update on Thursday.

The country has plunged more than $850 billion into debt and will be $184.5 billion in deficit by the end of this financial year.

The unemployment rate is expected to peak at 9.25 per cent before Christmas, leaving another 240,000 people out of work.

"We can see the mountain ahead and Australia begins the climb," Mr Frydenberg told reporters in Canberra.

Victorian Premier Daniel Andrews has announced $300 support payments for anyone awaiting coronavirus test results, if they aren't entitled to paid sick leave.

Almost 90 per cent of people who caught the disease in Victoria over the past two weeks did not self-isolate between feeling sick and getting tested, according to data cited by Mr Andrews on Wednesday.

More than half didn't stay at home while waiting for their results.

Federal Health Minister Greg Hunt stressed the importance of self-isolation.

"If you are being tested, you do have to isolate. If you are ill and showing symptoms, please stay away from work," Mr Hunt said.

"These are the critical things that will protect us."

Health authorities are particularly concerned about aged care workers.

"If you have any symptoms at all, however minor, you must stay at home and not go and work anywhere else until you have been tested and cleared," Chief Nurse Alison McMillan told reporters.

"Please do that to protect not only yourself, but your family, and all of the people you work with and those you care for."

There are now 1470 Australian Defence Force personnel in Victoria helping with contact tracing, testing, traffic checkpoints and logistics.

Mr Hunt said more troops would be deployed if necessary.

He has asked all states and territories to set aside a contingency reserve workforce to assist Victoria during its coronavirus outbreak, should the state plunge into a "worst case scenario".

The Victorian government is considering what further restrictions may be needed to stop the virus spreading.

Australian Medical Association president Tony Bartone said it would be a disaster if the state's lockdown continued until Christmas.

"Clearly we need a circuit breaker," he told the Nine Network.

"We need all Melburnians to understand this is serious and this is really now about everyone doing the right thing."

Dr Bartone said outbreaks in aged care facilities were "just a heartbeat away from a calamity".

A Sydney nursing home has been closed to visitors after a staff member tested positive, with NSW recording 19 new cases.

A NSW school, childcare centre, supermarket and cafe have also undergone deep cleaning after being exposed to the virus.

Face masks or coverings are now compulsory in greater Melbourne and Mitchell Shire because of high levels of community transmission.

Australian Associated Press