Victorian authorities are urging people in and around Apollo Bay to have coronavirus tests after viral fragments were detected in wastewater.
Testing of sewage samples collected in Apollo Bay has shown fragments of SARS-CoV-2, the virus that causes COVID-19.
It was detected on Friday from a sample collected from the entry pipe to the sewage treatment plant last Tuesday. Further testing has confirmed the positive result.
People in Apollo Bay and surrounding areas with even mild symptoms are being urged to get tested.
More than 60 locals have already been tested since the weekend with no positive results to date.
Testing of up to 300 sewage samples a week is now taking place at 25 surveillance sites across the state to detect the spread of the virus.
Melbourne Water's Nick Crosby said the results were well validated and a similar approach had previously been used to monitor the spread of polio.
He said researchers were working on methods to ensure samples could be traced back to particular suburbs as case numbers continued to fall.
"In a (Melbourne) population of five million, we do have two large treatment plants. One covers two million and one about 1.8 million," he said on Wednesday.
"If you get a detect, it will be very challenging to find an individual or a small cluster without an efficient traceback."
People who have been infected may shed the virus or virus fragments on used tissues, off their hands and skin when washing or in their stool.
It can take several weeks for people to shed the virus, making it a potentially valuable detection tool as the number of cases detected through routine testing reduces.
Victoria is collaborating with other states and New Zealand in a research project to better understand the presence of viral fragments in wastewater testing.