States are ramping up coronavirus testing and strict border controls as they desperately try to stop Melbourne's outbreak infecting the nation.
Victoria recorded 165 of Australia's 182 new cases of the disease on Thursday, with the source of 135 under investigation.
Prime Minister Scott Morrison has urged people to be patient as tougher border measures come into force.
"We do not want to see the situation in Victoria repeated in any other part of the country," he said.
South Australia will force all returning residents to be tested for the disease within 24 hours and then again after 12 days.
All people who have spent time in Victoria will be asked to come forward and get checked regardless of whether they have symptoms.
Queensland will fine anyone, including residents, who has travelled from interstate and refuses to be tested.
Victorians will be turned around at the border rather than given the chance to go into quarantine at their own expense.
Western Australia will tighten its hard border, stopping anyone who has been in Victoria for the past two weeks from entering.
Tasmania has extended a state of emergency, due to end on Thursday to the end of August because of the Melbourne outbreak.
Victoria has been isolated from other states with military and police patrolling the NSW and SA borders.
International flights are also set to be capped to ease the burden on the hotel quarantine system.
Mr Morrison will discuss the issue with state and territory leaders on Friday.
"I will be taking to national cabinet a proposal that would ease the pressure on our points of entry," he said.
Flights into Melbourne have stopped as infections rise.
Other capital cities are struggling to cope with rising numbers of passengers, who must spend two weeks in hotel isolation.
Plans to return international students to Canberra have been shelved after the ACT recorded four coronavirus cases in two days.
The nation's chief medical officers have been asked to investigate the hotel quarantine system after major failures in Melbourne fanned dozens of new infections.
Mr Morrison declined to criticise the Victorian Labor government over its handling of the regime.
"I can understand that many, many people in Victoria will be feeling very frustrated at the moment, and many are very angry," he said.
"I'm aware of where they're directing that frustration and anger but it won't help the situation if I were to engage in any of that."
Hard lockdowns for people living in eight Melbourne public housing towers will end, but the strict measures will continue for one block which has had 53 positive tests.
In NSW, there were 13 new cases with 11 detected in returned travellers, one a contact of an existing case and the other from interstate.
WA's three new cases were all from hotel quarantine.
© AAP 2020