New South Wales has recorded 356 new local cases of Covid-19, a new grim record for the state.
There were also four Covid-related deaths reported: a woman in her 80s, a man in his 80s and a man in his 70s. All had not been vaccinated.
An additional death was recorded in a man in his 80s who caught the virus abroad and tested positive in hotel quarantine.
Of the new cases, 147 are linked to existing outbreaks and the source of infection for 209 cases is under investigation.
NSW Health Minister Brad Hazzard blamed lockdown rule-breakers for the state's worsening outbreak, saying authorities "can't legislate against "stupidity, arrogance and entitlement".
"If people applied the rules, if they complied with the rules and law and applied an element of common sense and modicum of decency to the rest of the community, we would be fine," he said.
The vast majority of NSW is now in lockdown, with residents of Greater Sydney, Tamworth, Armidale and Byron Bay subject to stay at home orders. That's around 6.5 million people, or about 80 per cent of the state.
With cases continuing to climb, there are fears further regions across the state could be locked down in the days ahead. There were no additional cases recorded in Armidale, Tamworth or the Hunter today.
Burnett Institute CEO Brendan Crabb told the ABC that NSW residents will likely be barred from entering other parts of Australia until at least Christmas.
He said it was "pretty likely" NSW would be shut off from other states and territories for months to come as a result of the state's outbreak.
"If the rest of Australia stays with the national policy of zero-Covid, there is no option, but to shut themselves off as best they can," he said.
"There is just every likelihood that this is going to continue until the best part of Christmas in this sort of on-off lockdown or lockdown for different regions at different levels."
Epidemiologist Tony Blakely echoed Crabb's comments, telling 7 News that residents in the regional areas of NSW should expect more frequent snap lockdowns for at least the "next three months".
He said stay at home orders would continue as the NSW government had "pretty much lost control" of the virus.
While lockdowns would be less common outside NSW, Blakely warned they will likely still happen until Australia's vaccination rate climbs higher.
"For places outside of New South Wales, we hope to be using [lockdowns] infrequently but they will occur from time to time," he said.
Victoria has recorded 20 new local cases of Covid-19, but only five of those cases have been in quarantine throughout their infectious period.
There are now more than 12,000 active primary close contacts isolating across Victoria.
The Health Department says there are 2000 primary close contacts linked to Heathdale Christian College, 1500 linked to Islamic College of Melbourne, 500 linked to Ilim College and 700 linked to Mount Alexander College.
In the Al Taqwa community, more than 90 per cent of primary close contacts have already returned a result.
Lockdown extension in Melbourne likely
As Victoria's regions emerge from lockdown this morning, Premier Daniel Andrews revealed Melburnians will have to achieve consecutive days with all new coronavirus cases in isolation for their entire infectious period before lockdown is lifted in the big city.
Andrews said yesterday that Victoria had asserted "a degree of containment" around the outbreak in Melbourne, allowing regional communities to exit the week-long lockdown early at 11.59pm local time last night.
Melbourne is still scheduled to follow suit and exit lockdown on Thursday, but sources close to the Health Department told The Herald Sun this was becoming increasingly unlikely.
Andrews said the number of new cases who had been infectious in the community was the most important metric to watch in the coming days.
"We're still chasing [these outbreaks] very hard," he said. "We're not out in front of this yet, I think we're running alongside it, but we're not yet in front of this particular outbreak."
Victoria recorded 11 new cases on Monday, all linked to the known outbreaks. However, only one of them was in quarantine during their infectious period which means Melbourne may have some work to do before the lockdown ends.
Andrews said it was "far too soon" to make a definitive judgment about an extension of the current restrictions.
"Things can move rapidly but I just can't predict what's going to happen on Thursday... it's not a tick and flick. It's a detailed process the government goes through to determine what is proportionate," he said.
Queensland has recorded 3 new community cases of Covid-19 overnight, all linked to the Indooroopilly cluster in the southeast.
Those cases were not in the community while infectious and are all in quarantine.
Premier Annastacia Palaszczuk thanked Queenslanders for their efforts during lockdown to quash the Indooroopilly cluster.
Nevertheless, she warned the state was "not out of the woods yet" and that extra precautions would need to remain in force.
Continued restrictions in southeast Queensland include: home gatherings limited to 10 people; a cap of 10 people gathering in public spaces; and a cap of 20 people for weddings and funerals.
Given Victoria had been plunged into its sixth lockdown a week after it was released from its fifth, Palaszczuk said Queenslanders "should be under no illusion" that the next outbreak could happen at any time.
"We are seeing this Delta strain take hold in countries all around the world. We have to go on what the best advice is about going hard and going fast," she said.
In Cairns, health authorities have now traced the source of a mystery infection which was the catalyst for the far north city being plunged into a three-day lockdown from Sunday.
Residents were ordered to stay at home after a taxi driver was found to have been infectious in the community for 10 days.
The cause of the man's infection was a mystery and health authorities had feared a widespread outbreak in the state's far north but chief health officer Jeannette Young said genome sequencing had revealed a connection between the driver and a reef pilot who tested positive last week.
"We suspect it was when he drove that pilot from his home to the airport and then that pilot slid down to Brisbane, so we're checking all of those [links] and making sure we are have all of them," she told reporters on Monday morning.
Queensland recorded four new locally acquired cases on Monday but all were linked to the Indooroopilly cluster and detected while in home quarantine.
Of the four new cases reported on Monday, three were connected to the Ironside State School — a teacher, a student's parent and a household contact — and the other was a household contact of a Brisbane Grammar School student.
Young said the continued escalation of case numbers linked to the school cluster despite all new cases being in home quarantine was further evidence of the importance of stay-at-home directions for close contacts.
"We all have to remember that the incubation period is 14-days so it is really important that people, all of those 12,000 people, do stay and adhere to that quarantine as we go forward."