Grampians Public Health Unit medical director Rosemary Aldrich confirmed all primary close contact to an active Daylesford COVID case has tested negative to the virus by Monday. Associate Professor Aldrich said the unit was confident exposure to a healthcare worker from Melbourne, who worked overnight in a residential disability setting late last week, had been contained.

These follow a nursing student from Melbourne who tested positive after attending a practical class at Australian Catholic University's Ballarat campus earlier this month.

Ballarat's last new recorded COVID infection was August 24 last year and the city's residents have been COVID free for more than a year.

Associate Professor Aldrich said the Daylesford case set a good example as an individual in their response and for adhering to COVID-safe measures before they knew they were infected. She also said Spring Medical's response and the way the cases workplace, in the hospitality sector, had safe measures in place were telling in the negative COVID results so far.

But this was also a stark reminder for everyone to remain vigilant.

This comes with a clear warning from Victoria's COVID response commander Jeroen Weimar about authorised workers conduct themselves in regional Victoria.

Mr Weimar made a point of highlighting the disability worker in Ballarat to media on Monday, who unknowingly brought the virus to the region.

Victorian treasurer Tim Pallas also announced a crackdown on COVID safety in construction, a mostly young, mobile workforce proving to be a "major source of transmission".

All three active COVID cases in Ballarat the past fortnight have travelled from Melbourne.

Associate Professor Rosemary Aldrich said Ballarat had a robust healthcare system, a city well-prepared and these factors had set the region in good stead in responding to emerging cases in the past - and people needed to keep doing the right preventative measures.

"As we've seen with some of those regional cases, and indeed the two exposures now we've had in our region, people unknowingly, without any idea they are infectious, have come into our region or at least have been exposed by going to Melbourne and then returning - it's as easy as that, it's as simple as that," Associate Professor Aldrich said.

"We do know there's a lot of traffic and a lot of people who are needing to go to Melb to work or are coming from Melbourne for permitted reasons. As a community we need to be very careful and cautious in how we interact, even though we're not subject to the same stringent lockdown conditions of metropolitan Melbourne.

"...We are fortunate to have freedoms from that severe level of lockdown but I don't think that takes away from being careful and cautious in everything that we do."

Victoria recorded 473 new COVID infections on Monday, including six in regional VIctoria - three in Mildura, three in Geelong and all linked to existing contacts.

IN OTHER COVID NEWS

Mr Weimar confirmed on Monday a Melbourne resident had worked in a Ballarat residential disability facility in an overnight shift last Thursday to Friday. He did not reveal the site in question, only to say there were 10 primary close contacts and of the four residents there, three have been vaccinated.

Associate Professor Aldrich did also not reveal the site, due to privacy, but said the city's disability care sector had been identified for early vaccinations and the centre linked with this case had taken up the offer.

Mr Weimar said the worker was permitted to be working in Ballarat at the time, before they experienced symptoms.

"For authorised workers moving into regional settings, you're able to do so by the nature of your work but please be very careful for whom you contact," Mr Weimar said.

"As we've seen with the case of our Ballarat worker, the potential for you to be taking the infection from Melbourne into regional Victoria is significant, it's very real and 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.

"So we please ask all authorised workers who are going legitimately into regional Vic to be very, very careful."

Mr Weimar also warned essential workers, unable to work from home, to take particular care. He called out tea-rooms as a high-risk area as shown in the virus' spread among construction workers and transmission from a V/Line worker that sent hundreds of co-workers into isolation and continues to impact train services across regional Victoria this week.

"It's where we probably drop our guard the most, it's where we physically drop our masks, to eat and to drink. It's also where we see people from different shifts and different workplace bubbles still interacting with each other," Mr Weimar said.

"Tea-rooms are not safe places, in fact, for many of us at work they are probably the most dangerous place."

Meanwhile, COVID fragments detected in Ballarat South wastewater continues to be a concern for Grampians Public Health Unit.

Associate Professor Aldrich confirmed on Monday there had been four detections in three days last week - two on Wednesday and two on Friday. The latter, she said, could be explained by the disability care worker from Melbourne who later tested COVID-positive but this did not account for the fragments found on Wednesday.

Fragments could be an indicator of someone shedding the virus but Associate Professor Aldrich said the results with cases in the region were probably a sign of further exposure in Ballarat.

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