The sharp rise in infections around Melbourne is not yet proof that the virus is "out of control", experts say, but it will be a different story if cases don't stop climbing over the next in the next two days.
Victoria recorded 428 new cases on Friday, which is 111 cases more than the state's previous daily record, established on Thursday.
Of those new infections, 370 are under investigation.
Victoria's Health Minister Jenny Mikakos told reporters on Friday the state is facing " a once-in-100-year event".
"This is a serious situation," she said. "We are in the fight for our lives."
Victoria's Chief Medical Officer Brett Sutton said the numbers are "both disappointing and concerning".
"We have not turned the corner here ... so it has to turn around. I have spoken for some days about a hope that numbers stabilise but also said there is no guarantee of that," Prof Sutton said.
He said "there is a hope" that numbers stabilise over the coming days to reflect the impact of metropolitan Melbourne's lockdown.
"That is my hope, that no-one is being complacent here, and we are all thinking about the additional measures that may be required if it does not turn around to we are not just banking on the idea that if we wait long enough those numbers will stabilise and drop so we must bear in mind any additional measures that are important to help control the numbers."
But it begs the question: If the lockdown hasn't impacted the curve as predicted, how could Victoria's daily numbers go? Experts who spoke to news.com.au were reluctant to speculate, but said they were concerned by the current trend.
Professor Raina MacIntyre, from UNSW, said: "The numbers should start to come down soon. I was expecting to see them come down by now, but the fact that they have not is concerning."
Professor Adrian Esterman, from the University of South Australia, said: "I think we were all hoping it would stabilise around the 300 mark.
"If we also see community transmissions with unknown contact keep rising, then it is a worrying trend.
"I think another couple of days 'results are needed before we can call it out of control. It is only nine days since level 3 [restrictions] were introduced, and I was expecting it take a week and a half to two weeks to take effect."
WHO advisor and UNSW epidemiologist Mary-Louise McLaws said: "Watching daily numbers doesn't easily reveal a pattern. But over incubation periods, the speed of transmission is slowing ever so slightly. Little soon to see impact of stage 3 plus (the use of face masks)."
Premier Daniel Andrews used Friday's press conference to call for individuals to stop breaking the rules.
"We saw last night some coverage of a couple of people who had travelled from Coburg [in Melbourne's north] to Rye on the Mornington Peninsula," the Premier said.
"It is a 200km round trip. That is not daily exercise. That is a day trip and day trips are not on. There is nothing about that that is compatible with staying at home.
"If you can walk, if you want to go for a walk then you can go for a walk close to home.
That makes sense. Otherwise, if you are literally taking 200km round trips, that will do nothing but spread the virus.
"I am sure people would love to go to a more scenic location ... but this is not a normal winter. As we approach this weekend, it is not a normal weekend. These numbers are very challenging and we always said it would worse before it got better."