Victoria has recorded 15 new coronavirus cases and one fatality, bringing the state's death toll to 807 and the national figure to 895.
The figures, confirmed by the Department of Health and Human Services on Tuesday, bring Melbourne's 14-day case average to 10.6, down from 11.6 on Monday.
Melbourne's total number of mystery cases between 20 September and 3 October is 13.
The city needs a 14-day average of fewer than five cases as well as less than five mystery cases before it can further ease restrictions.
Asked if Melbourne would meet the targets by 19 October as planned, Chief Health Officer Brett Sutton replied: "I really can't say".
"We can get to a point where there are significant numbers of cases every day and it drops off dramatically because they're all being chased up, those other close contacts have been contained and then you suddenly see a decrease in numbers," he told reporters on Tuesday.
He confirmed 28 cases are now linked to the Butcher Club and Chadstone Shopping Centre cluster, an increase of four since Monday.
The cluster consists of at least eight staff, 11 family and household members of existing cases and four customers of the Butcher Club.
One of the cases visited the Oddfellows Cafe, in Kilmore, 60 kilometres north of Melbourne, before they knew they were infectious and infected a cafe worker.
A close contact of the cafe worker has also tested positive.
"That individual, as far as I know, was not aware that they were a close contact at the point of time that they were travelling," Prof Sutton said, noting they were in the area for a permitted work reason.
"So it wasn't that they were breaking quarantine, it was that they weren't aware that they were a close contact of a positive case."
Prof Sutton said any Melburnian travelling to regional Victoria for a permitted reason must not stop to shop or eat out.
On Monday, he also said it was possible Melbourne's 5km travel restriction could remain through the next round of eased restrictions.
The government previously had said the rule, which bans people from traveling more than 5kms from their home unless for essential activities, would be lifted at the next stage of restriction easing.
But Prof Sutton said all options, including extending the ban to 10kms, were on the table.
"I honestly don't know. I wouldn't rule out anything," he said.
"I don't think we are going at all in a direction that would make it tougher, but going out to 10kms is a consideration amongst all options."
He said the 5km rule had been part of a suite of successful policies in limiting movement and stopping the spread of the virus outside of postcodes where it already existed.
Additional reporting by Jarni Blakkarly.
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