Masks will be compulsory in all indoor settings in Victoria after the state recorded 11 new COVID-19 cases, all stemming from the NSW outbreak.

Masks will once again be compulsory indoors in Victoria, as part of efforts to stem an outbreak of the highly infectious Delta COVID-19 variant in the state.

From 11.59pm on Wednesday, anyone aged over 12 will be required to wear a mask in all indoor settings, including schools and workplaces, unless an exception applies.

Masks must also be worn outdoors when social distancing isn't possible.

AAP understands discussions are also under way to reimpose caps on crowd limits and restrict the number of visitors permitted in homes, although no decision has been made.

It comes as 11 new cases of COVID-19 emerged in Melbourne's north and west on Wednesday from two separate outbreaks, both of which stem from NSW.

A teacher from Bacchus Marsh primary school is among the 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 man, aged in his 60s, is one of four residents of the apartment to test positive on Wednesday.

He also infected his parents, aged 89 and 90, who live in Craigieburn, and visited multiple stores at Highpoint Shopping Centre on Friday.

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 Thursday while infectious, forcing some 200 residents into 14 days of lockdown.

COVID-19 Commander Jeroen Weimar said the three removalists, two of whom have tested positive, weren't wearing masks, in a breach of their worker's permit conditions.

The trio also did a drop off at a Craigieburn home the same day, and are believed to have slept in their trucks on Thursday night before travelling to SA.

Mr Weimar said the next two days would be critical to stamp out the outbreaks.

"We are right on the heels of this particular outbreak," he told reporters on Wednesday.

Meanwhile, the state and federal governments are bickering over financial support for NSW.

Prime Minister Scott Morrison on Tuesday announced a new, joint state- and federally-funded support package for NSW due to the Sydney outbreak that has infected more than 800 people and claimed two lives.

The package will also be offered to other jurisdictions if they have to impose extended lockdowns.

Premier Daniel Andrews' office issued a statement on Tuesday night accusing the federal government of NSW favouritism, while federal Treasurer Josh Frydenberg said people were "sick" of Mr Andrews' "whingeing and his politicking of the crisis".