Victorian authorities are racing to find the source of a new local coronavirus case in a testing site traffic controller, on the state's first day out of lockdown.
Health Minister Martin Foley confirmed the traffic controller at the Moonee Valley racecourse drive-through testing centre worked at least two days while infectious.
The young man, who was wearing a mask during his shifts, developed symptoms on Monday evening and was tested the next day before the result emerged on Wednesday morning.
The testing site in Melbourne's northwest is closed and dozens of staff who worked the same shifts as the man, who was sent home to isolate as a precaution.
"We do believe there will be minimal risk to those at the site," Mr Foley told reporters on Wednesday.
Chief Health Officer Brett Sutton said the case was a concern, given the man is not a primary close contact of a previous case and hasn't been linked to Victoria's current outbreaks.
"But we are in early minutes, if not hours, of understanding exactly what's happened, where it might have been acquired," he said.
Contact tracers are interviewing the man to determine his movements and identify close contacts, while pathologists are investigating whether any positive cases went through that testing centre.
Professor Sutton said it was more likely the man caught the virus from an infected person in a car than the other way around, but urged anyone with symptoms to get tested and isolate.
"The risk to individuals coming through in their cars is extremely low," he said.
"But if you've wound down a window to speak to a traffic controller at that site that might put you at a slightly greater risk."
A petrol station, two supermarkets and a shopping centre in Frankston and Frankston South have been listed as new tier two exposure sites, dating back to Saturday.
The new case, detected after the midnight deadline, was announced on top of eight new locally acquired infections reported earlier on Wednesday.
Those cases have been linked and were in isolation for their entire infectious period.
Prof Sutton said the result was "terrific news", though reinforced the message that the outbreak was not over.
It comes as Victorians tasted freedom on Wednesday after a 12-day statewide lockdown was lifted.
Under eased restrictions until August 10, Victorians can travel across the state and leave their homes for any reason but must continue to wear masks indoors and outdoors.
A ban on home gatherings remains but people are able to meet outside in groups of 10.
Restaurants and cafes are welcoming back guests for seated service only, while retail traders and gyms have resumed operating.
In a relief for parents, the state's one million students returned to schools and they were also free to work from the office again in limited numbers.
Despite the lockdown ending, the annual Royal Melbourne Show has been cancelled for a second straight year, with organisers citing the challenges and risks of hosting large crowds in the pandemic.
Meanwhile, Victorian businesses hit hard by repeated coronavirus lockdowns will be able to apply for new relief grants as part of a $400 million package jointly funded by the state and federal government.
Treasurer Tim Pallas conceded the cumulative effect of the state's five lockdowns had dented businesses confidence to reopen.
"This should be seen ... as a very optimistic shot in the arm for business to get on and trade," he said.
Australian Associated Press