Victoria’s chief health officer says he was not sure Melbourne will meet its virus roadmap targets, despite infections dropping to nine cases and no deaths on Monday.

“My gut feel is that it will be a line ball. Look, it’s not a certain one way or the other,” Brett Sutton told a media conference.

The clock began ticking on Melbourne’s final two weeks before restrictions are expected to be wound back.

With case numbers continuing to fall, Victorian authorities have also announced a plan for all students to return to face-to-face learning in schools within weeks.

Monday’s zero fatalities was the first day day since September 15 there were no new COVID deaths.

The new infections take the city’s crucial 14-day average to 11.6, down only slightly on Sunday’s 11.9.

• Tenth day without community virus infections in NSW

On the state government’s original plan to relax coronavirus rules, it must be below five by October 19 for Melbourne to take its next step.

That would mean Melburnians are no longer restricted on when they can leave home, public gatherings of up to 10 will be allowed, retail and hospitality businesses can reopen.

The state government’s other key benchmark for winding back virus rules from October 19 is fewer than five mystery cases statewide.

On Sunday, Victorian health authorities admitted they were worried about a series of mystery infections, which have ticked up in recent days.

But Dr Sutton on Monday said a higher number of cases might not stop the city moving to more relaxed rules.

“We’ve always said that we need to look at what those cases are. If the outbreak numbers are part of that 14-day average that we get to on October 18 or 19, we will look at exactly how well that’s controlled,” he said.

“We can [also] have more than five mystery cases. We’d have to see exactly where we were at at that time including the trend.”

The outbreak linked to a butcher at Chadstone Shopping Centre continues to grow. Photo: AAP

The cluster linked to Chadstone Shopping Centre grew to 24 on Monday. It includes one infection in regional Victoria, in the Mitchell Shire just north of Melbourne.

There was also a new mystery case on Monday in Shepparton, north of Melbourne.

The suspected infected person has no links to known outbreaks, and the confirmed infection is from a rapid result test used in regional Victoria. The patient has been retested.

“It’s not a definite positive at this stage. We’re treating it as a positive – we need to do that. But all of the public health actions are in place in terms of isolating that case and managing those close contacts as close contacts would normally be managed,” Professor Sutton said.

On Monday, state Education Minister James Merlino announced a new plan for Melbourne students to return to classrooms. VCE and VCAL students and all primary school children begin term four this week, while year seven students go back on October 12.

Mr Merlino said students in years three-10 would return from October 26.

“This is the light at the end of the tunnel,” he said.

All children in regional Victoria also returned to school this week.

On Sunday, Premier Daniel Andrews said he was “as confident as you can be” that Victoria’s 14-day average would meet the key benchmark of fewer than five within a fortnight.

“Regional Victoria is in a different place today than they were three or four weeks ago. And hopefully on 18 or 19 October, so just in a couple of weeks’ time, metro Melbourne will be in a different place than they are right now,” he said.

The Victorian toll from the pandemic is 806 (nationally, it is 894).

-with AAP