Victorians are bracing for bad news as a longer lockdown looms, while parts of NSW are on high alert after a Melbourne man with coronavirus crossed the border.
There are also renewed calls for an overhaul of hotel quarantine after a man became infected in Perth.
Victorian authorities are expected to extend the state's seven-day lockdown, due to end on Thursday night, as concerns grow about rapid transmission.
The 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.
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.
The Australian Medical Association is calling for urgent changes to hotel quarantine after a man was infected by a returned traveller in the room next door in Perth.
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 told a Senate hearing.
"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.
While there are 366,000 people employed in aged care nationally, 32,823 have received both doses through Commonwealth visits to nursing homes.
There are several other ways to receive vaccinations but the national figures are not recorded.
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."
