New South Wales has recorded 452 new local cases of Covid-19, with the source of 323 of those cases still under investigation.
A woman in her 70s who had Covid-19 died last night, NSW Health reported, taking the death toll in the Sydney outbreak to 57.
NSW Premier Gladys Berejiklian said a staggering 75 per cent of cases in NSW are people under 40, emphasising the danger of the virus spreading among young people.
Berejiklian said vaccination uptake was the pathway out of lockdown. Almost 52 per cent of the state's adult population has had at least one jab, she said, but the goal was to get 70 per cent fully vaccinated before restrictions could be eased.
"I want to make this very, very important point: life will be much freer than what it is today once we get to 70 per cent and 80 per cent [fully vaccinated]," she said.
"It doesn't mean we'll be completely free. It doesn't mean that we will let the virus be rampant in the community no matter our number of cases, but it will be freer than it is today."
Asked by reporters on Sunday when the state could expect to get new case numbers down to zero, Berejiklian said eliminating the Delta variant was "not possible".
"We have to learn to live with it," she said. "But the best chance we have to live with it freely and safely is to get the case numbers down as low as possible."
NSW entered a statewide lockdown on Saturday and the government ordered a police operation to enforce compliance across Sydney.
Operation Stay At Home has seen NSW police and Australian Defence Force officers deployed across the state after officials blamed rule-breaking for the continued growth of the outbreak.
NSW Police Commissioner Mick Fuller said the focus for officers would be to enforce the new public health orders - including a five-kilometre rule for exercise and heavier fines for lying to contact tracers - as well as assisting health authorities.
Elliott has also urged citizens to report illegal family gatherings and household visits.
"I implore members of the community to consider Crime Stoppers as one of the most useful and important weapons in the war against Covid," he told the Sydney Morning Herald. "Do not underestimate its ability to gather vital intelligence for police."
Berejiklian warned NSW could reach 1000 new cases a day "if people keep ignoring the rules" and the 21-day police operation failed.
Victoria today recorded 24 local cases of Covid-19. Of the new cases, 21 are linked to known outbreaks but only 14 were in isolation throughout their infectious period.
After the Melbourne outbreak grew by 22 cases yesterday, the Victorian government imposed tight new restrictions that took effect from midnight and will last until 11.59pm on September 2.
A night curfew, taped-off playgrounds and worker permits have been implemented across Melbourne after health officials warned Victoria was in danger of following NSW's disastrous path.
Victorian chief health officer Brett Sutton said yesterday the state was "right on the cliff edge" of an explosion of coronavirus 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 curfew is in effect from 9pm to 5am. People in Melbourne are not permitted to leave their home except for limited reasons.
Sutton said the curfew was a difficult but necessary measure to prevent the outbreak from worsening and prolonging the lockdown.
"The evidence around curfews is not dissimilar to evidence around a whole bunch of other interventions," he said.
"It is one of a suite of interventions that was very successful last year in Victoria."
Epidemiologist Mike Toole told The Age the effect of Melbourne's stage-four restrictions last year had worked, though it was impossible to establish which particular measures had been the most effective.
He said the curfew would be a "game changer" for lockdown compliance.
"It brings us back to the full package of stage four last year," Toole said. "And we know that it worked."
Melbourne mayor Sally Capp wrote on social media last night that she hoped residents could find ways to "unwind safely" amid the tighter restrictions.
"We'll get through it together. Stay strong Melbourne," she wrote.
The ACT recorded 17 new cases of community transmission today, taking the capital's cluster to a total of 45.
"We are, of course, though, very early in this outbreak. Our case numbers are going to continue to grow," ACT Chief Minister Andrew Barr told reporters.
"The last two days have been two of the biggest days ever for the ACT in terms of new cases during the pandemic. That's why we extended the lockdown yesterday."
The ACT lockdown is now scheduled to end on September 2 at the earliest.