Australia's death toll from the coronavirus is on track to pass 300 fatalities after Victoria recorded its deadliest day on record, as federal health authorities restated their confidence a vaccine will be found.
But National Deputy Chief Medical Officer Nick Coatsworth also said that while the development of a COVID-19 vaccine continues at a "very exciting pace", Australia currently has only "two blunt tools" to tackle the virus.
"Tools like extreme social distancing and the stage four restrictions that are in place down in Victoria at the moment," he told reporters in Canberra on Sunday.
"As we prepare, as we trial vaccines, as we prepare for the possibility of a vaccine, we must at the same time keep our distance."
Ten of the 17 Victorian deaths - a new one day record - confirmed on Sunday were linked to aged care outbreaks. There were also 394 new Victorian COVID-19 cases confirmed.
The latest deaths have lifted the national toll to 295 and the Victorian toll to 210, and the growing number of fatalities shows no sign of abating.
But in Victoria, which is the national epicentre of the latest outbreak, police are still doling out a high number of fines for coronavirus restriction breaches.
"It's ... the sort of behaviour that will mean this second wave goes longer than it should," Victorian Premier Dan Andrews warned on Sunday.
Federal Agriculture Minister David Littleproud lamented Victoria's situation, which erupted just as it appeared the virus was coming under control across the country.
"We braced ourselves for victory and its been snatched away from us through the actions of a few," he told Sky News' Sunday Agenda program.
"That just goes to show how vulnerable we are to this virus and every protocol needs to be lived up to."
Some federal Victorian MPs, including Treasurer Josh Frydenberg who is now undergoing two weeks of quarantine in Canberra so he can attend the next sitting of parliament from August 24, have criticised the Andrews government's handling of the outbreak.
But shadow assistant treasurer Stephen Jones said there was clearly existing problems in the aged care sector, most of which is overseen by the federal government and other sectors.
"When there's a crack in the dam and everyone is working around the clock to catch that up, I don't think it's a time when we should be searching for who's responsible for putting the crack in the dam," he told reporters.
Meanwhile, Finance Minister and Western Australian senator Mathias Cormann has done an about-face to back WA Premier Mark McGowan's decision to close the state's border to everyone, except in special circumstances.
"This has been an evolving situation. People's assessments have changed," Senator Cormann told ABC television's Insiders program.
"Given what has been happening in Victoria and given where the country is at, we support the current state border arrangements, including here in Western Australia."
Elsewhere, NSW recorded just 10 new infections in the 24 hours to 8pm on Saturday, including a Hornsby Hospital healthcare employee in northern Sydney who worked on August 6 from 11am to midnight while infectious.
Queensland went for a fourth straight day with no new cases.