UPDATE, 12pm: A Melbourne resident infected with COVID-19 has been confirmed to have been working in Ballarat.
Victoria's COVID Commander Jeroen Weimar confirmed on Monday morning a disability care worker had attended a residential disability site last week.
He did not reveal the site in question.
"They were infectious on the 9th and 10th of September, when they worked an overnight shift," Mr Weimar said.
"There's 10 primary close contacts. Of the four residents there, three have been vaccinated."
Mr Weimar said the worker was permitted to be in Ballarat at the time, but it served as a reminder for essential workers from Melbourne to be extra vigilant.
There are still no further exposure sites listed in Ballarat on the health department website.
See where all the exposure sites are here.
"For those authorised workers who are moving into regional settings, you are able to do so by the nature of your work but please be very careful for who you come in contact with," he said.
"The potential for you to be taking the infection from Melbourne into regional Victoria is significant, it is very real.
"It will be down to the strength of the workplace procedures and how you conduct yourself in regional Victoria as to whether you pass it on to other people."
Health minister Martin Foley said the worker was vaccinated, but could not confirm if they had received one or two doses.
Meanwhile, there were six new cases officially recorded in regional Victoria.
Three of the cases are in Geelong and the other three are in Mildura.
All six are primary close contacts.
The Melbourne worker at the disability care house in Ballarat does not count in this tally, as the worker lives in Melbourne.
Ballarat has not had a new COVID-19 case since August 24, 2020 and has been officially COVID-free since September 9, 2020.
There were no further cases detected in the Daylesford region following the confirmed case on Friday last week.
EARLIER: Victoria has recorded 473 new local COVID-19 cases, as case numbers continue to soar throughout the state.
Of the 473 new cases, 202 have been linked, meaning 271 are currently classed as mystery cases.
It is the highest daily figure that has been recorded in the state this year.
There is not yet any information on whether any deaths occurred.
There were 30,032 vaccinations administered and 49,037 tests received on Sunday.
Details and locations of the cases will be revealed later today.
The new figures come as COVID-19 continues to show greater signs of spreading into into the regions.
There were more than a dozen cases recorded in the regions over the weekend, including a confirmed case in Daylesford.
In Ballarat, there have been multiple detections of COVID-19 in the wastewater, with a warning going out the city is "more probable than possible" to have an active case.
Almost all regional trains have also been cancelled, with more than 300 V/Line staff in isolation due to an outbreak within staff.
Meanwhile, Victorians can expect to soon get a more detailed roadmap out of COVID-19 lockdown, as much-anticipated modelling inches closer to completion.
Premier Daniel Andrews has flagged the state government will receive detailed modelling from the Burnet Institute in coming days, before the "caveated" blueprint is laid out "in about a week's time".
The modelling will allow health authorities and ministers to formulate plans about what businesses can open and when, on the path to fully vaccinating 80 per cent of Victoria's eligible population.
The state government has previously announced a minor easing of restrictions when the state hits 70 per cent first-dose coverage, including an extra hour of outdoor activity and the expansion of the five-kilometre travel radius to 10km.
By Sunday, 66.2 per cent of the eligible Victorian population had received at least their first dose.
A plan to return students to classrooms, including upgrading ventilation in schools and staggered entry times, will form part of the more comprehensive roadmap.
Health authorities are currently investigating a significant outbreak at a Melbourne school, with The Age reporting its principal repeatedly flouted lockdown rules by inviting parents to send their children.
Deputy Chief Health Officer Dan O'Brien said the outbreak at the Fitzroy Community School in North Fitzroy had grown to at least 30 cases involving students and staff.
Children aged from 12 to 15 years will be able to get a Pfizer vaccination in Victoria from Monday.
Schools and COVID-hit areas are also preparing to welcome a series of pop-up vaccination hubs to boost coverage rates, with the program to begin over the next two weeks.
Of the 392 new cases reported on Sunday, 255 were from Melbourne's north and another 89 came from the western suburbs.
The federal government has embarked on a three-week vaccination blitz of the areas, sending an extra 417,000 Pfizer and Moderna doses to Victoria.
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