Victoria has recorded six new locally acquired Covid-19 cases overnight as Melbourne's outbreak continues to grow.
Acting Premier James Merlino announced a further case, one of the six, had been identified on Wednesday after the midnight reporting cut-off, taking the state's community cases to 15.
"We are very concerned by the number and kinds of exposure sites," he told reporters.
Health authorities are now mulling over further measures to control the spread of the virus, with Mr Merlino saying he "cannot rule out" tightening restrictions for Greater Melbourne.
"The next 24 hours are going to be critical," he said.
Eighty of 301 primary contacts identified have so far returned negative test results. The results of those individuals and their movements in the community if positive will be key in deciding whether a lockdown is needed, Chief Health Officer Brett Sutton said.
The Department of Health has identified more than 40 exposure sites across the city while thousands of AFL fans are on high alert after one of the cases linked to the northern Melbourne outbreak attended the MCG over the weekend.
Wednesday's official total is 10 local cases, five of which were identified throughout Tuesday and include a man in his 60s and four family contacts in the same unit.
Virus spreads to Melbourne's south
Three of the latest cases are workplace contacts of one of those family contacts. The workplace is a finance firm located in Port Melbourne
There are also two other contacts linked to that individual.
One overnight case is linked to the initial case of the cluster in Whittlesea.
Mr Merlino said it was a "good thing" tracers had so far managed to link all the cases.
Health authorities have genomically linked the outbreak to a Wollert man who tested positive to the virus earlier this month after quarantining in one of South Australia's medi-hotels, however they have not yet found a direct link between him and any of the cases.
There were more than 26,000 tests in the previous 24 hours.
The Department of Health are now trying to establish all of the exposure sites linked to the new cases.
Health Minister Martin Foley identified three bars as locations of particular concern which were visited by a positive case in Melbourne's inner south on Saturday night.
Anyone who attended Circus Bar in South Yarra between 1.30am to 4.15am on Sunday morning, Three Monkeys bar in Praham between 9.10pm and 11.00pm and 12.30am and 2.00am, and Somewhere Bar in Prahan between 10.30pm and 1.00am must get tested and quarantine for 14 days.
Do you have a story tip? Email: firstname.lastname@example.org