Four of today's cases are still under investigation and eleven are linked to current outbreaks, with just eight in quarantine throughout their infectious periods.
A commendable 40,737 Victorians came out for testing yesterday, but president of the Australian Medical Association of Victoria warned it's mystery cases that are of the "greatest concern".
"Anytime there's a mystery case, it's indicating that there's somebody out there that is spreading COVID-19," Roderick McRae told Today.
"They may not be symptomatic, they may be mildly symptomatic, they are clearly not attending for testing and they are transmitting the virus. It's of great concern.
"While we have these unaccounted for and mystery cases, it just is not safe to open up all business and we all understand that business is hurting. They're really hurting.
"But it's just not safe. Nobody is aware of where any person coming into their business has been for the last two to five days."
He said authorities were desperately working to avoid Victoria seeing the number of cases being recorded daily in New South Wales, where 345 infections were reported yesterday.
"The spread in NSW is looking like a slowly erupting volcano and the lava is just flowing through," he said.
"Everybody is very concerned, should the virus get into the Indigenous communities. So, we do need to have all of these control mechanisms."
Victoria's cases have remained around the same for the past few days, sitting around 20 per day.
Dr McRae said health care workers were particularly susceptible to the mystery cases gripping hotspot areas.
"One of the difficulties is that a lot of the staff in the public hospitals, in the emergency departments, in the general wards, all live around the vicinity of the various hospitals,' he said
Dr McRae said if those healthcare workers go to their local shopping centres where the virus is being transmitted by mystery cases, they are then facing a 14-day quarantine which takes them out of their viral roles.
"And so we need to have a mechanism so we know how it's safe to operate the hospitals, ensure there's adequate staffing," he said.
"We may have to quarantine some staff and wait for them to be able to come in and replace staff who are already having to be quarantined in their home."