Greater Shepparton has so far avoided another lockdown but anyone with the "slightest of symptoms" in the Shepparton, Orrvale and Kialla areas have been urged to get tested and isolate until receiving a negative result after the third positive wastewater test in the catchment between August 9 and August 16.
"We are continuing to see a number of what we call unexpected detections of COVID-19...in the wastewater system. While the testing program isn't necessarily a smoking gun, it does provide a good signal and another line of intelligence for us to follow," Acting Chief Health Officer Ben Cowie said.
"Sometimes they are the result of somebody who is shedding but no longer infectious. Sometimes, it is from a case that we know about who is safely isolating...But when we don't know of any cases isolating in an area, that's when we call it unexpected detection, and that's when we really pay attention.
"Testing numbers have increased substantially (in Shepparton), but we can do more, so please anyone with the slightest of symptoms come forward and get tested."
Thirteen of Thursday's cases have been infectious while in the community and 44 have been in isolation, health authorities say.
Of the cases in isolation, 38 are linked to Al-Taqwa College, three cases are associated with Glenroy West Primary School, one further case is linked to the Caroline Springs shopping centre, one is linked to Newport Football Club and a further case has been linked to a previously reported community case.
Three further cases are associated with St Kilda East community gatherings, three are household contacts of previous cases, one is linked to a Lygon Street Apartment and three are linked to a Malvern East pizza shop.
There have been three further mystery cases in Glenroy, Ascot Vale and Doncaster.
"57 seems a very big number...but when the vast majority of those have been in isolation for their infectious period, that's exactly what we want, that is the system working exactly as it should work," Premier Daniel Andrews said.
"The numbers are important, but the story that sits behind those numbers is more important."
Exposure sites have swelled above 550 overnight but none have been added in regional Victoria since the latest Delta outbreak began.
The new cases were detected from 49,607 test results, with 27,581 vaccine doses administered across state-run sites.
Yesterday's vaccination numbers push Victoria beyond the milestone of two million COVID-19 vaccine doses administered across state-run vaccination sites since the roll-out began.
There are now 296 active cases of COVID-19 across the state, with three people being treated in intensive care including one person on a ventilator.
The news comes with 681 cases of COVID-19 reported in NSW overnight and one further death - a man in his 80s.
NSW Premier Gladys Berejiklian has confirmed the lockdown in regional NSW will be extended for a further week until August 28 in a push to eliminate the virus from regional areas.
Regional NSW was due to emerge from lockdown this weekend.
"We've got to continue to be very worried about the regions...it is right we stay in front of the curve, in front of the spread and keep regional and rural NSW in lockdown," NSW Deputy Premier John Barilaro said.
Anyone leaving Sydney will now require a permit to do so, with Sydneysiders no longer able to travel to their holiday home "for a weekender".
More to come.
