New South Wales has recorded 681 new local cases of Covid-19 - with the source of infection for 511 of those cases under investigation - as the state's crisis continues to worsen.
An additional Covid-related death was also reported by NSW Health, taking the death toll in the latest outbreak to a total of 61. The new death was of a man in his 80s. He had received one dose of vaccine and had underlying health conditions.
There are currently 474 Covid-19 cases admitted to hospital in NSW, with 82 people in intensive care, 25 of whom require ventilation.
Since the Sydney outbreak began in mid-June, there have been 9,950 local cases reported.
Despite Greater Sydney enduring almost two months under stay at home orders, the fact that there are now more than 4000 unlinked mystery cases across NSW means new daily cases are likely to grow into the thousands in coming weeks.
In total, there are 4,314 cases in this unlinked category – making up a massive 40 per cent of cases in the current outbreak. The vast majority of them are in the 12 local government areas of concern in Sydney.
NSW Premier Gladys Berejiklian and chief health officer Kerry Chant confirmed yesterday the numbers will rise – saying that the current virus reproductive rate of 1.3 shows the worst is yet to come.
It means every 10 infected people could spread the virus to 13 others – and the reproductive rate needs to fall below one to ensure NSW can get on top of the community spread and drive down case numbers
"We haven't seen the worst of it," Berejiklian said yesterday.
"You have to assume, no matter where you are in the state, that every time you set foot out of your door, that you have the virus or anybody you're in contact with has the virus."
Given the dire situation, health experts have warned NSW residents to brace themselves for very high case numbers in the weeks ahead.
Leading epidemiologist James McCaw, who advises Australia's federal government, said he would not be surprised if the state recorded up to 2000 daily cases within a month.
"Our models show the possibility of increases and decreases, but I think it's more likely to be well over 1000 and up to 2000 within a month or so," he told the Sydney Morning Herald.
He said it could drop, too, but that it was "deeply concerning" there were still thousands of unlinked cases, meaning the situation was likely to deteriorate rather than improve.
In Victoria, experts fear that lockdowns could be continually reimposed due to NSW's growing crisis and repeated cross-border seeding events that have proven difficult to stop.
Victoria recorded 57 new local cases of Covid-19 today, more than double the new cases from previous days. Of the new cases, 54 are linked to known outbreaks and 44 have been in isolation for the entirety of their infectious period.
Public health expert Professor Maximilian de Courten has warned the harsh restrictions in Melbourne, which now includes a night curfew, could be imperiled by the situation in NSW.
"It's a numbers game and absolutely the more cases in NSW, the higher risk to other states like Victoria," he told The Age. "Some modelling suggests even if we get down to zero and open up, the virus will break through in four to six weeks, causing a lockdown. That may be even faster with cases so high. It's this yo-yo lockdown situation that nobody wanted."
Victorian Premier Daniel Andrews said on Monday the state was at a "tipping point" in controlling the latest outbreak.
"We see too many cases. We see too many mystery cases," he said.
"I don't want to have to stand here and report deaths. I don't want to have to stand here and report hundreds and hundreds and hundreds of cases every day and perhaps an even greater number of people in hospital."
After the Melbourne outbreak grew by 22 cases on Monday, the Victorian government imposed tight new restrictions that are scheduled to last until 11.59pm on September 2.
A night curfew, taped-off playgrounds and worker permits came into effect across Melbourne from Tuesday after health officials warned Victoria was in danger of following NSW's disastrous path.
Victorian chief health officer Brett Sutton said on Monday the state was "right on the cliff edge" of an explosion of cases after a number of lockdown breaches, including an engagement party attended by 69 guests.
"We are at the brink and we need to step back from the brink," he said.
The night curfew is in effect from 9pm to 5am. People in Melbourne are not permitted to leave their home except for limited reasons.
Canberra has recorded 16 new local cases of Covid-19 as authorities in the Australian capital work to contain an outbreak that has grown to a total of 83 cases.
Five of the new cases are still under investigation, and the rest have been linked to previous cases.
Of all the cases in the outbreak, a total of nine have not yet been linked to other infections, Australian Capital Territory Chief Minister Andrew Barr said.
"This is a crucial time in our public health response," he told reporters on Thursday. "Please stay at home and support this effort. We need to drive these case numbers down to zero."
The ACT was supposed to get out of lockdown this Thursday but the stay at home orders have been extended until September 2.
Meanwhile, Queensland has recorded another day of no new Covid-19 cases after crushing the Indooroopilly high school cluster in the southeast earlier this month.
Queensland Premier Annastacia Palaszczuk has repeatedly thanked residents for adhering to earlier lockdown restrictions to halt the spread of the virus.
The state also tightened its border zone rules on Monday given the deteriorating situation in NSW.
NSW border zone residents can now only enter Queensland for obtaining essential goods and services that can't reasonably be obtained in NSW.
"The situation in NSW continues to be very concerning," Queensland's chief health officer Jeannette Young said at the time.
"Given the escalation of local restrictions, we have no choice but to put in place a tighter border situation to protect Queenslanders."