Victoria has recorded 466 new cases of coronavirus since yesterday, and 12 further deaths.
A male in his 30s, who was not a health care worker, is among those who have died - six deaths are associated with aged care settings.
More than 600 people are in hospital.
"We have currently 998 health care workers who are active cases; that's an increase of about 140 since yesterday," Premier Daniel Andrews said in his daily update.
"There are just under 7100 cases in metro Melbourne under stage four, and just over 500 cases in regional local government areas under stage three.
"That's two very different sets of circumstances, those settings are important though; with 500-plus cases in regional Victoria, it's very important that we move to that stage three."
Mr Andrews said he understood frustrations for regional people in areas "seemingly COVID-free", but the numbers warranted regional Victoria being put back under restrictions.
"We know that's deeply inconvenient ... but we need to do everything we can to keep those numbers low," he said.
"Their sense of frustration at seemingly being COVID-free [in some regional communities], and yet having these sorts of restrictions, I can appreciate that ... but at the same time, with the number of mystery cases that we have across the state, and indeed some in country Victoria, we have to assume there is more virus ... than the data tells us.
"That abundance of caution is critically important."
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The Chief Health Officer's in-depth breakdown is expected later this afternoon, but as of Friday evening, the North East remained without active cases.
An active case listed for Moira Shire on August 4, which Yarrawonga Health was not aware of, was removed from yesterday's LGA tally.
Chief Health Officer Brett Sutton believed the reproduction number of the virus was below one.
"We're headed in the right direction. That 0.9 really needs to be a 0.5 ... I think stage four restrictions will head us in that direction," he said.
"That effective reproduction number will also be altered by how many people stay home when they're unwell.
"We need people to isolate from the moment they first get symptoms."
Mr Sutton said the number of "mystery cases" had reduced, and there was some stabilisation in overall numbers.
"Tracking the proportion of community cases, or mystery cases, as a percentage of the total over the last month has had some positive signs," he said.
"We've seen a proportion at about 16, 17 per cent early in July, and it increased up to 26, 27 per cent and then its come back down."