Australia could be on track to eliminate coronavirus, according to Victorian Chief Health Officer Brett Sutton.
Professor Sutton confirmed Victoria recorded four new cases of Covid-19 today, although two were "weak positives" and may be removed from the state's tally.
"We will have an expert review panel look at the results and make a call on them definitively as positive or negative," he told reporters.
The other two cases are under investigation and include someone who had the virus in the past but is likely no longer infectious.
Professor Sutton said one of the cases being investigated had been "in and around" the Deer Park area before testing positive.
"Until we know more about the potential exposure sites, potential movements of this individual and other close contacts that we can identify, I would encourage anyone who is symptomatic, especially in Deer Park, to look for a testing station nearby," Professor Sutton said.
He thanked 23,583 Victorians who were tested on Thursday, calling them "heroes".
"They are the individuals who mean that we can identify any last remnants of virus that might be circulating in Melbourne and that we can end it," Professor Sutton said.
He said the risk of a third wave was "minimal" but would not be zero until a vaccine was produced.
The state, however, could eliminate the virus "by virtue of finding everything that is out there".
"We're not hanging our hats that, because there could be hidden cases, there could be chains of transmission that go on without being detected," Professor Sutton said.
Asked if Australia could eliminate the virus, he replied: "It's absolutely possible."
"There's a grumbling number of cases in NSW but it's within our grasp and if it's a by-product of everything that we're doing routinely for each and every case, then fantastic," he said.
The nation is undertaking a suppression strategy that is focused on reducing transmissions to ensure hospitals are not overwhelmed.