Victoria had recorded no further local cases of Covid earlier on Thursday on top of the 10 reported a day earlier to narrowly avoid being plunged into a fifth lockdown.
Health officials have since confirmed two more cases linked to an AFL match between Geelong and Carlton at the MCG last Saturday, included a nine-year-old boy.
The outbreak has grown to 16 cases associated with two chains of transmission.
More than 1500 primary close contacts have been plunged into 14 days of isolation along with another 5,000 secondary close contacts.Insurance Loans Mortgage Attorney Credit Lawyer
'The next 24-48 hours that is a critical period to see whether this is a wave that's standing up on us, or whether we're cresting over the top,' Victoria’s Covid-19 commander Jeroen Weimar said.
'We'll have a better picture soon.
Masks are once again compulsory indoors throughout Victoria as officials try to stem two outbreaks of the highly infectious Indian Delta variant transported into the state by two Sydney removalists and a returning family.
Victorian Premier Daniel Andrews and senior ministers met on Wednesday night and Thursday morning to discuss the possibility of a snap lockdown, but held off.
Victoria officially recorded 10 locally-acquired cases on Thursday, which were all cases announced on Wednesday.
This includes three teachers at two separate schools, one who caught the virus from an infected friend at an AFL game at the MCG on Saturday.
Th MCG is among 75 exposure sites flagged by Victorian health officials.
A group of removalists, two infected with coronavirus, have sparked an outbreak in Victoria that leaves the state teetering on the edge of lockdown after visiting several venues and even travelling to South Australia
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Eleven new infections were found in Melbourne's north and west on Wednesday from two separate outbreaks, both of which stem from NSW (pictured, a Melbourne local)
From 11.59pm on Wednesday, anyone aged over 12 in Victoria is required to wear a mask in all indoor settings, including secondary schools and workplaces, unless an exception applies.
Hospitality venues could also be affected with numbers slashed and the no standing while eating or drinking rule reinstated at bars, restaurants, clubs and functions.
This will mean dancing and singing in licensed venues could also be banned, but no firm decisions had been announced as of Wednesday night.
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, as well as the Young & Jackson hotel, with an infected friend who lives at the now locked-down Ariele Apartments in Maribyrnong.
So far, 2,000 footy fans who were at the clash on Saturday have been told to get tested and isolate.
DFU Uni Hill shopping centre (pictured) in Bundoora was revealed as an exposure site late on Wednesday night, after an infected case shopped at Nike, Adidas, Asics, Puma, Cotton On and Connor
- From 11.59pm on Wednesday, anyone aged over 12 in Victoria will be required to wear a mask in all indoor settings, including schools and workplaces, unless an exception applies
VISITORS TO THE HOME SLASHED
- There is currently a cap of 15 people allowed to attend home gatherings, but it is expected that figure will be greatly reduced in an announcement on Thursday
HOSPITALITY NUMBERS CUT
- Hospitality venues could also be affected with numbers slashed and the no standing rule while eating or drinking to be reinstated at bars, restaurants, clubs and functions
- This will mean dancing and singing in licensed venues could also be banned
PROTOCOLS FOR COMMERCIAL AND FREIGHT OPERATIONS TIGHTENED
- It is not yet clear what restriction will be brought in for interstate freight workers, but stricter check-ins, face masks and other protocols could be part of the announcement
The man, aged in his 60s, is one of four residents of the apartment complex 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, a friend of the Ariele Apartments case, attended a staff day on Monday but had no contact with students on Tuesday or Wednesday.
He is understood to have infected two household contacts, one of whom is also a teacher at the same school.
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.
Millions of residents in Melbourne are bracing a new wave of Covid restrictions after two infected Sydney removalists transmitted the virus during a trip to Victoria last week (pictured, a woman in Melbourne)
The Ariele Apartments in Maribyrnong, Melbourne (pictured) is at the centre of a Covid outbreak after the infected Sydney removalists spent several hours there - spreading the virus to at least four people in two households
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 - the second of their children - 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.
The crew had the necessary travel permits to enter Victoria, but their movements are now under the microscope.
Covid-19 Commander Jeroen Weimar said the three removalists, two of whom have tested positive, weren't wearing masks.
Young & Jackson Hotel in Melbourne's CBD (pictured) has been flagged as an exposure site after a coronavirus-infected man from the Ariele Apartments dined there with a friend before a match at the MCG. That friend, a teacher, now also has the virus
Vic Health personnel wearing PPE enter Ariele Apartments in Maribyrnong (pictured) where infected Sydney removalists spread coronavirus to at least four residents
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.
Two of the removalists have tested positive back in Sydney and the other remains in isolation.
City of Hume, Craigieburn, clusterA family of four returning from New South Wales have all tested positive - a 40-year-old couple and their two children A 30-year-old man caught the virus from the family at Coles in Craigieburn Central
Maribyrnong clusterTwo Covid infected removalists spent four hours in the Ariele apartment complex Three people living in one apartment have since tested positive. Another 60-year-old man living in the building also caught Covid and has since passed the virus onto his