Victoria has recorded 15 new locally acquired coronavirus cases, including four mystery cases.
The health department on Friday confirmed 11 of the new cases are linked to known outbreaks, while eight were in quarantine during their infectious periods.
Some 40,737 tests were processed in the 24 hours to Friday morning, while 27,427 Victorians were vaccinated at state-run hubs.
It comes as contact tracers race to find the source of four other mystery cases recorded on Thursday.
Three of the cases are across two separate households in Glenroy, including a child who attends Glenroy West Primary School.
Victoria’s COVID-19 Commander Jeroen Weimar said the families don’t know each other and their children don’t attend the same school or sports club.
COVID-19 has been detected in wastewater in the Glenroy area since 5 August.
The other mystery case, a man who lives in Brunswick East, has some social connections to known exposure sites and authorities are confident a definitive link will be found in coming days.
There are now more than 400 exposure sites across Melbourne and its urban fringe, including inner-city tram routes, an Australian Taxation Office building in Moonee Ponds and VicRoads site in Hoppers Crossing.
Seven shops in the South Melbourne Market were listed as tier-one sites overnight after an infected person attended Saturday from 1.30pm. The market has closed for cleaning.
It comes less than a month after the market was forced to close due to another COVID-19 outbreak.
Meanwhile, the state’s health department said COVID-19 fragments had been detected in the Camberwell-Balwyn area of Melbourne’s eastern suburbs, and two catchments in the city’s west including Tarneit, Truganina and Williams Landing.