Eleven new local Covid-19 cases in Melbourne have triggered new restrictions for Victorians as health authorities race to contain the virus.
From Thursday, anyone in Victoria aged over 12 will be required to wear a mask in all indoor settings, including schools and workplaces, unless an exception applies.
Meanwhile the ABC reports Victoria will place caps on home visits later on Thursday.
Melbourne was put on high alert on Wednesday after the emergence of two separate outbreaks – both linked to Sydney's surging Delta outbreak.
And further restrictive measures are expected as Premier Daniel Andrews and health authorities deliberate over what additional restrictions will help in fending off the virus, including reduced home visitors.
Epidemiologist Nancy Baxter, head of the Melbourne School of Population and Global Health, told ABC Radio on Thursday morning it is likely another lockdown was imminent for Melbourne.
"The pace of the positive cases is quite concerning," she said.
"I wouldn't be surprised if in the next 24 hours they've made a decision to put us back in lockdown."
The Department of Health's testing chief Jeroen Weimar hinted such a move was coming on Wednesday saying authorities are "not going to take any chances".
“We will always take fast and aggressive action as we think is appropriate,” he said.
Two Melbourne outbreaks explained
One of the outbreaks has emerged in Melbourne's west and the other in the city's north.
A teacher from Bacchus Marsh primary school is among the new cases, having reportedly attended an AFL match between Carlton and Geelong at the MCG on Saturday with an infected friend who lives at the locked-down Ariele Apartments in Maribyrnong.
The friend, aged in his 60s, is one of four residents of the apartment block to test positive on Wednesday.
He also infected his parents, aged 89 and 90, who live in Craigieburn.
Bacchus Marsh Grammar has confirmed the infected teacher attended a staff day on Monday but had no contact with students on Tuesday or Wednesday.
Staff have been told to self-isolate and get tested, while the school's Woodlea and Maddingley campuses will be closed for the rest of the week.
Barwon Heads Primary School near Geelong has also been closed until further notice after a case of coronavirus was reported.
Another new case is a man in his 30s who attended Coles Craigieburn at the same time as a member of a family who recently returned from Sydney infected with COVID-19.
The family of four from Melbourne's northwest were required to self-isolate at home as red zone permit arrivals, but one visited the Coles and a Metro petrol station in Broadmeadows.
All have now tested positive, with the fourth infection confirmed on Wednesday.
The Ariele Apartments outbreak is linked to a NSW removalist crew who did a pick up at the complex on July 8 while infectious, forcing 200 residents into 14 days of lockdown.
Mr Weimar said the three removalists, two of whom have tested positive, weren't wearing masks, in a breach of their worker's permit conditions.
More than 50 exposure sites have been listed across the state, with a range of DFO Uni Hill stores in Bundoora and an Epping medical centre added to the list late on Wednesday.
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