There are now three local cases of Covid-19 in Ballarat.
Two additional cases were confirmed overnight after a construction and worker tested positive on Monday.
Chief Health Officer Brett Sutton said it was likely there would be more cases.
"We have had positive wastewater detections from the eighth,” he said.
"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."
Medical Director at Grampian's Public Health Unit ROSEMARY ALDRICH says anyone who is feeling unwell should get tested.
'We ask our community to get tested even if they have the slighted of symptoms," she said,