Fragments of COVID-19 have been detected in Warrnambool wastewater after a routine sample was taken on Tuesday.
The Department of Health has advised of an 'unexpected' detection reported in the last seven days, with wastewater samples returning a negative result weekly until September 21.
The department said the Warrnambool area included Allansford, Dennington and Koroit, with the period of interest September 19-21.
The last instance of a positive wastewater sample in Warrnambool occurred on January 27.
It comes as a positive wastewater sample was also identified in Hamilton on September 20, with the period of interest being between September 18-20.
Authorities are assessing whether the detection in Hamilton was linked to COVID-positive workers who attended the Pedrina Park Pavillion construction site on Tuesday and Thursday last week.
The department said the detections could be an undiscovered new case or cases, or they could be the result of one or more people in the area who have recovered from COVID-19 but are still shedding the virus.
Anyone who lives in, works in or has visited the areas above is urged to watch for the mildest of COVID-19 symptoms and get tested as soon as possible if symptoms develop.
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