Victorian health authorities say lockdown "is working" as statistics reveal some promising news as the state battles its latest coronavirus outbreak.
The state announced 22 new locally acquired cases on Wednesday, almost double the 13 cases reported on Tuesday.
However Health Minister Martin Foley told reporters that 73 per cent of new cases were isolating for their infectious period, as opposed to just six per cent two days ago.
"So what this means is that our contact tracers and our restrictions are working in tandem, as part of the public health teams toolkit to beat this virus back and to beat this outbreak back," he said.
"That should give us confidence that this is a process that is working, and it is working because millions of Victorians are doing the right thing."
The 22 new cases is the highest daily spike in cases in the state in 10 months, however Chief Health Officer Brett Sutton sad while the number may have looked concerning, 16 had been in isolation for their entire infectious period.
"It is a really good sign that has changed dramatically in the last couple of days, I expect it to be improving over time," he said.
"It may even be that within a couple of days we don't see anyone who's been out in the community for any of their infectious period.
"Can you imagine what situation we could be in if we hadn't locked down when we locked down?"
State avoids 'thousands' of new cases
Professor Sutton said if the state had entered lockdown today rather than last week when cases emerged, the state would be reporting thousands of cases over the coming weeks.
"Delta is a variant that takes off from dozens to thousands of cases within just a matter of weeks," he said.
"If we locked down today instead of when we did, we would get thousands of cases over the next couple of weeks because of where we've gotten to even in lockdown now."
Professor Sutton added the state would be in a "world of hurt" if that was the reality.
"it's very hard to demonstrate what you're avoiding, but I think we would be in a world of hurt, not so much today, but we'd be in a world of hurt over coming weeks if we hadn't done what he did," he said.
Victoria announced lockdown two days after it recorded the first case of its latest outbreak, while South Australia took the same action a day after its first case.
NSW did not lock down Greater Sydney until 10 days after it recorded the first case of the latest outbreak.
Warning over 'fast-moving' variant
Mr Foley said half of Wednesday’s new locally acquired cases were household contacts of primary close contacts.
“So the important work in isolating, both as primary contacts and through that their contacts has been really significant,” he said.
“It was important in 2020, it’s even more important in 2021.
“As a result of the fast-moving nature of the Delta variant … which definitely moves through household contacts at a rate of knots … if Victoria wasn’t managing those secondary close contacts as tightly as we are now … this virus would have got beyond us already.”
Victorian Premier Daniel Andrews extended the state's lockdown on Tuesday, with it now due to end on July 27.
Mr Andrews defended the decision to extend lockdown, saying he did not want the state to be in the same position as NSW.
Mr Andrews said the state had avoided a "NSW-style, long, lengthy, very challenging lockdown" but authorities needed more time to "extinguish" the outbreak.
Do you have a story tip? Email: firstname.lastname@example.org