Two "likely" cases of COVID-19 have been picked up in Melbourne's northern suburbs after traces of the virus were detected in wastewater samples.
Victoria's 86-day streak without locally acquired cases is now at risk as the probable cases undergo urgent retesting.
On Monday morning, Victoria's Department of Health confirmed it had been notified of two "likely positive" cases in the city's north.
"It is currently understood the two individuals are connected," the department said in a statement shortly after 10am (local time).
"A full investigation is underway into these results, and initial public health actions are being put in place while both individuals isolate and are urgently retested."
The department said it will communicate any specific public health advice as soon as possible when investigations and interviews are complete.
"Until then, remember to observe key COVID-safe behaviours: get tested if you have any symptoms at all, check in at all venues, and always wear masks on public transport, including rideshare vehicles."
The news follows the detection of COVID-19 fragments in the wastewater surrounding the northern suburbs of Epping and Wollert. Last Friday, Victoria's chief health officer Brett Sutton issued an alert to Epping residents, warning locals to be "aware of" the emerging situation. A Woolworths store in Epping North was subsequently listed as an exposure site.
A Melbourne man also tested positive for the virus on May 11 after returning from India on April 19. He contracted COVID-19 during his 14 days of quarantine at Adelaide's Playford Hotel.
In its case update on Monday afternoon, the Ministry of Health confirmed it is aware of the reports.
"We will be working with our counterparts in Australia. We expect to be able to provide a further update later today," a spokesperson for the ministry said.
The press secretary for COVID-19 Response Minister Chris Hipkins also confirmed that health officials are in talks with their Victorian counterparts.
As reported by 7 News, New South Wales chief health officer Kerry Chant has described the situation as being in its "preliminary" stages.
"I think it provides a warning to the community," she told local media.
On Monday, the Victorian government launched a crackdown on commuters shunning the state's mask mandate, with a AU$200 (NZ$215) fine for those caught flouting the health measure on trains and trams, according to 7 News.
The Ministry of Health and the office of COVID-19 Response Minister Chris Hipkins have been contacted for further comment.
