New South Wales has recorded 753 local cases of Covid-19, with the source of infection for 619 of those cases still under investigation.
Of the new cases, only 63 were in isolation throughout their infectious period.
There are currently 608 Covid-19 cases admitted to hospital in NSW, with 107 people in intensive care, 34 of whom require ventilation.
NSW has today reached its six million vaccination target, a week ahead of schedule, and Premier Gladys Berejiklian has vowed to announce "extra" freedoms now the target has been met.
Berejiklian has repeatedly emphasised vaccination uptake as the key to relaxing lockdown restrictions after giving up on elimination earlier this month. About 31.5 per cent of the NSW population over the age of 16 have now been fully vaccinated, while 59 per cent have had their first dose.
"What is really important to note is that while case numbers are going up, the more important figure going up is the vaccination rate," she told reporters yesterday. "The vaccination rate is where we can look forward to living life freely."
Berejiklian said no state was immune to the Delta strain and that lockdowns had proven ineffective in stamping out new outbreaks.
"We have seen examples in other parts of Australia where even under very strict lockdown conditions, the virus keeps growing. That's how insidious it is," she said.
"There will always be debate about going too hard, going to soft. We started off with 11 cases in New South Wales, 17 overnight when we went into lockdown, and it just demonstrates that no matter how hard we work and no matter if 99 per cent of people are doing the right thing, there is an element of Delta that nobody can control."
The Greater Sydney lockdown was implemented ten days after the state's first case in the current outbreak was recorded in mid-June. There have now been 13,765 cases reported since that first infection.
Victoria recorded 50 new local cases of Covid-19 today. Of the new cases, 40 are linked to current outbreaks and 10 are under investigation. Only 11 cases have been in quarantine throughout their infectious period.
The state government's plan to lift the statewide lockdown in just a few days is now looking almost impossible as new daily cases remain high.
Most concerningly for authorities, there has fourfold rise in mystery cases in the past week and hundreds of infected children – meaning the planned end of "short and sharp" lockdown on September 2 now looks increasingly unlikely.
A government source told The Age it was highly probable the current restrictions would be extended because the number of mystery cases and of cases not in isolation were both rising.
About 45 per cent of the 381 cases recorded in the past seven days were infectious in the community. Premier Daniel Andrews said almost all new cases needed to be in isolation before the lockdown can be eased.
The state recorded 71 local cases on Monday. Of those cases, only 49 were linked to existing outbreaks, meaning 22 were mystery cases.
When asked if there was any chance of getting control of the outbreak by September 2, Victoria's Covid-19 commander Jeroen Weimar said he remained hopeful.
"If we continue to work together, we have pulled six, seven outbreaks now in the last eight months, so collectively as a Victorian community we can absolutely do that," he said. "We can cap the rising cases and get it down, because if we don't, we are looking at [NSW] and that's what is awaiting us."
Melbourne University epidemiologist Tony Blakely has suggested a "soft lockdown" as an alternative approach if the outbreak cannot be contained by early September.
If the state shifted to a soft lockdown in September, vaccination rates would catch up with new case numbers, his modelling showed.
"A soft lockdown would see your cases peak at about 300 or 400 per day, and then start to come down as you caught it by November," he told the ABC. "So that's one option. It's really just putting it out there for discussion at the moment."
Queensland has recorded two new local cases of Covid-19 in truck drivers who travelled into the state from NSW.
Premier Annastacia Palaszczuk said they were not considered a "high risk" and had not visited too many places. Both cases remain under investigation.
Queensland eased some restrictions on Friday after crushing a Delta outbreak of 145 cases earlier this month. At the peak of the outbreak, 19,000 people were having to self-isolate.
Griffith University infectious diseases expert Professor Nigel McMillan told the ABC a fast lockdown and high testing rates were key to Queensland's success.
"We went early and we went pretty hard, and we've had a good mask-wearing mandate. We had really good buy-in from people in terms of testing and that gave us confidence to come out of lockdown," he said.
The ACT has recorded 30 new Covid infections overnight, bringing the Australian capital's outbreak to a total of 167 cases.
Of the new cases, 25 were linked to existing cases while five remain under investigation. 11 were infectious in the community.
ACT Chief Minister Andrew Barr said there were now four Canberrans in hospital and one in intensive care.
The ACT went into lockdown on August 12 after a man in his 20s from the north Canberra suburb of Gungahlin tested positive.
The lockdown is currently set to end on September 2.
Experts divided on reopening plan
Australia's national plan to reopen the country once vaccination rates of 70-80 per cent are achieved has led to conflicting evaluations by the nation's top health and economic researchers.
According to new modelling from the Australian National University, if Australia reopens with 70 per cent of Australians aged over 16 fully vaccinated, there could eventually be 6.9 million cases of Covid-19, 154,000 hospitalisations, and 29,000 fatalities.
At 80 per cent, the ANU predicts approximately 25,000 fatalities and some 270,000 cases of long Covid. To prevent mass deaths and hospitalisations, the ANU suggests a vaccination rate of at least 90 per cent, which includes children under 16, is needed.
However, the Doherty Institute, whose modelling underlies Australia's national plan, says reopening with high numbers of daily cases will still be safe once the country reaches the 70 to 80 per cent vaccination target.
The institute issued a long statement overnight saying Australia can reopen safely with hundreds of cases every day, saying the nation's focus must shift from 'zero-Covid' to keeping deaths to a minimum.
"Once we achieve 70 per cent to 80 per cent vaccination we will see less transmission of Covid-19 and fewer people with severe illness, and therefore fewer hospitalisations and deaths. Covid-19 won't go away but it will be easier to control in the future," the statement reads.
It points out that in an average year, Australia would suffer about 600 deaths and 200,000 cases of influenza – a level which can be managed by the national health system.
"In the Covid-19 modelling, opening up at 70 per cent vaccine coverage of the adult population with partial public health measures, we predict 385,983 symptomatic cases and 1457 deaths over six months. With optimal public health measures (and no lockdowns), this can be significantly reduced to 2737 infections and 13 deaths," it says.
Australian Prime Minister Scott Morrison, speaking with 7 News today, backed the Doherty Institute's modelling, saying "we have to get out of the cave" once the vaccination targets are reached.
"There will be cases, of course, but we've already seen this year for the vaccine that compared to the lockdown last year in Melbourne to what is occurring this year in Sydney, we are seeing far fewer cases of fatalities, far fewer cases of hospitalisation and that is what the vaccine achieves and that's why it assists us to get where we want to go," he said.
"We still have to live sensibly in a Covid-19 world. There will not be zero restrictions, there are common-sense baseline level restrictions."
Morrison also criticised Queensland and Western Australia for their continued commitment to eliminating the virus.
"Any state and territory that thinks that somehow they can protect themselves from Covid with the Delta strain forever, that's just absurd," he said.