Ballarat will join metropolitan Melbourne in its extended lockdown, meaning there will once again only five reasons to leave your home.

However, curfew rules will not apply.

Premier Daniel Andrews said with multiple wastewater detections, multiple exposure sites and four positive cases, Ballarat would be re-entering a seven day lockdown.

"We know this will be disappointing for the Ballarat community, but we would rather get on top of these cases and open up again as soon as possible," he said.

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"We know they will get around each other and get through this, they are a proud community and we will get through this together."

Chief Health Officer Brett Sutton said it was likely there would be more cases arise in Ballarat as part of the outbreak.

"There are likely to be more cases," he said.

"We have had positive wastewater detections from the eighth (of September). As we have said previously, that can sometimes mean someone passing through, someone who has recovered, but when subsequently you have confirmed cases identified, but does make you think that those wastewater detections related to someone who was positive and infectious and not detected in the community.

"So it has been over a week of likely transmission within the Ballarat community.

"So if you are in Ballarat, please stay alert, be aware of symptoms, get tested if you have been to any of the exposure sides or you have the mildest of symptoms, and if you have that opportunity to get vaccinated and you have no symptoms and haven't been to exposure sides, please step up for the vaccine."

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There is a walk-in testing centre at the Ballarat Respiratory Clinic on Dana Street, and a drive through on Skipton Street.

Mr Andrews said the vast majority of people in Ballarat have had a least one dose of the vaccine.

"It's so important that people in these LGAs continue to check for exposure sites near them, get tested if they have any symptoms at all and most important - get vaccinated if you haven't already," he said.

COVID Commander Jeroen Weimar said there would be additional testing capacity set up in Ballarat.

See where all the exposure sites are here.

There have been reports of lines hundreds of metres long already today as people come forward to get tested.

He also said the government was sending "thousands" of additional vaccinations to the city.

"We are working through setting up additional testing capacity across the city Ballarat at this point in time and we will be running extended operating hours for some of our testing sites," he said.

"We will make more announcements over the next 24-48 hours in terms of where they will be allocated to people can come forward and use this as a quick search to boost the vaccination rate in Ballarat to get through this outbreak."

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During the announcement, the Mr Andrews was asked why Geelong avoided lockdown but Ballarat did not.

There are more than 10 cases in Geelong and just three in Ballarat.

"I think a number of times, this is a sense of control in some parts and there is a sense that there is perhaps not control," he said.

The Greater Shepparton area will join the rest of regional Victoria and come out of lockdown from 11.59pm on Wednesday night.

"They've done an amazing job and this decision has come from the great work from the community," Mr Andrews said.

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