The Department of Health confirmed on Sunday morning confirmed 107 cases were linked to known outbreaks, with the source of 285 still under investigation.

It brings the total number of active cases in the state to 3112.

There were five new infections detected in regional Victoria, including in Greater Geelong, one in Mildura, two in Gippsland and one related to V/Line.

Health Minister Martin Foley said on Saturday the current outbreak was concentrated in the young and unvaccinated, with most of the state's active cases under the age of 40.

In the 24 hours to Sunday morning, 48,063 tests were processed and 36,534 Victorians received a vaccine dose at a state-run hub.

Schools are set to become a key part of the state's vaccination rollout to target students aged 12 years and older and staff, but also their families.

"These pop-ups are all about removing another barrier, taking the vaccination program to you," Premier Daniel Andrews said on Sunday.

"You can come and be part of that, get your first and second dose, play your part, get the lockdowns off and protect yourself against becoming seriously ill."

No additional exposure sites had been identified in the Ballarat area on Sunday morning, with one case and three exposure sites identified on Friday night in Daylesford creating large lines for pop-up testing on Saturday afternoon.

The Daylesford case was one of eight reported in regional Victoria on Saturday as the Health Department urged Ballarat residents to be vigilant about even mild COVID-19 symptoms.

In a statement, the department said:

"There have been repeat unexpected wastewater detections in the Ballarat South area from samples collected over the last fortnight.

"The detections could be the result of a person in the area who has recovered from COVID-19 but is still shedding the virus or it could be an undiscovered new case.

"Anyone who lives, works or has visited the following suburbs is urged to watch for the mildest of COVID-19 symptoms and to get tested as soon as possible if symptoms develop:

"Alfredton, Bakery Hill, Ballarat Central, Ballarat East, Ballarat North, Black Hill, Bonshaw, Brown Hill, Buninyong, Canadian, Cardigan, Delacombe, Eureka, Golden Point, Invermay Park, Lake Gardens, Lake Wendouree, Lucas, Mount Clear, Mount Helen, Mount Pleasant, Nerrina, Newington, Redan, Sebastopol, Smythes Creek, Soldiers Hill, Warrenheip and Wendouree."

It comes as all of Victoria's regional train services have been suspended on Sunday after more than 180 drivers and operational staff were placed in isolation following four positive coronavirus tests among workers.

READ MORE: V/line suspends trains after outbreak fears among staff

"Out of an abundance of caution we are suspending all trains on Sunday to limit the spread and to keep everyone safe," the Department of Transport said in a statement late on Saturday evening.

"Replacing trains with coaches will allow for services to continue to operate, give passengers certainty for Monday and help contain the outbreak."

Coaches will operate to an hourly frequency across most lines and not the scheduled Sunday train timetable.

The state has 147 people in hospital with COVID-19, up four from Saturday, with 34 of those people in intensive care units and 28 of them on a ventilator.

Of the cases in hospital, only one was fully vaccinated and isn't believed to be on a ventilator.

- with AAP

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