Several states remain on high alert as Victoria's coronavirus lockdown is extended for another seven days, with growing concerns about rapid transmission of the disease.
Melbourne's restrictions will now last until June 10, while conditions in regional Victoria will still ease from Thursday night.
Victoria's coronavirus outbreak has grown to 60 cases across more than 350 exposure sites.
One in 10 people who have tested positive caught the virus from a stranger.
Parts of NSW are on alert after a Melbourne man with coronavirus crossed the border, with South Australia also on guard.
Extra testing clinics are being set up in southern NSW after a Victorian man who tested positive for COVID-19 visited the area.
The man was on holidays with his family in NSW last week while potentially infectious.
He visited several locations around Jervis Bay, Hyams Beach, Vincentia and Goulburn on May 23 and 24.
The man drove back to Melbourne on May 24 before developing symptoms and getting tested.
He was one of the six cases recorded in Victoria on Wednesday, with most others family contacts of existing cases.
None of the new Victorian cases were in aged care.
There are also renewed calls for an overhaul of hotel quarantine after a man became infected in Perth.
The Australian Medical Association is calling for urgent changes after a man was infected by a returned traveller in the room next door at a Perth hotel.
State health authorities are investigating how the transmission took place.
It is the latest in a long list of breaches in hotel quarantine across the country.
"This would be the 21st (breach) according to our own records of issues within hotel quarantine," Chief Medical Officer Paul Kelly said.
"But we have to think about what the background is, that 352,000 people have come through hotel quarantine over that period."
Federal health officials said there had been no other transmissions detected in WA's hotel quarantine system after the case emerged.
Meanwhile, the aged care sector has called for solutions to boost the pace of the vaccine rollout.
The number of aged care workers who are fully vaccinated is unknown and many residents are yet to receive their second doses.
More than three months after the rollout began, less than two-thirds of nationwide aged care residents have received both doses of their vaccines.
The number is even lower in Victoria, where another outbreak has forced several facilities into lockdown.
Aged and Community Services Australia chair Sara Blunt said vaccination for staff should be made easier.
"The main issue right now is not whether the vaccine is mandatory, it's whether workers can get easy access," she said.
"If this means using the defence forces that have assisted in remote areas, or bringing in other resources to enable 'in reach' workplace vaccinations, then the government should make it happen."
Australian Associated Press