Chief Health Officer Brett Sutton, who has warned the state's second wave of coronavirus could kill more Australians, is set to review whether students in the locked down areas should return to school.

"I will give as much notice as I can around the resumption of school in those restricted postcodes," he said on Thursday.

"I want to see both that we're turning transmission around but also that we don't have such levels of community transmission, with students becoming infected, that our resourcing is all focused on response to cases in schools."

Also on Thursday, the state government confirmed veteran judge Jennifer Coate will lead the inquiry into Victoria's disastrous hotel quarantine program.

The program is on hold for a fortnight and Corrections Victoria is taking over its operation from private security.

Premier Daniel Andrews on Wednesday said genomic sequencing had traced a big proportion of coronavirus cases to breaches in hotels hosting returned travellers.

The inquiry will report its findings by September 25.

Professor Sutton said he wasn't aware of breaches from staff workers at the hotels, but hoped the inquiry would help reveal possible mistakes.

As authorities try to stem the outbreak, Prof Sutton said the focus was on transmission across communities.

He added engagement with families in hot spots had resulted in more children being tested, revealing cases that "would otherwise have gone unnoticed".

Victoria recorded 77 new coronavirus cases on Thursday, which brought the state's total to 2303, of which 415 are active.

Of the new cases, 13 are linked to outbreaks, 37 were detected through routine testing and 27 are under investigation. None are in hotel quarantine.

The increase in cases of community transmission linked to an unknown case hit 31 on Wednesday night.

Victoria has recorded double-digit case numbers for 16 days, particularly in Melbourne's northern and western suburbs, prompting localised lockdowns from Thursday.

Residents of these postcodes will only be able to leave their homes to shop for food and supplies, to receive or provide care, to exercise and to study or work if they can't do so from home.

Prof Sutton said a big proportion of the cases were detected in the hot zones, but not exclusively, and warned the continued growth meant more people could die.

"When you've got 70-odd cases every day, there is absolutely an expectation that some of those people will die," he said.

"That's why it's incumbent on all of us to be minimising our interactions with others."

He emphasised that all Victorians should reconsider seeing people in other households, including family and friends.

So far, 20 Victorians have died of the coronavirus.

There are now 20 patients in hospital, including four in intensive care.

"I certainly feel for people, and it's frustrating to see some areas where those restrictions aren't in place, just across the road from where you might be," Prof Sutton said.

"We all have to cop it on the chin. The alternative is that there's increased transmission and that there are more and more postcodes or all of metro Melbourne or all of Victoria that goes into a shutdown."

The state has had a total of 87 cluster outbreaks, Prof Sutton said.

A planned easing on restrictions for Victoria was delayed in June, with family gatherings quoted as one of the sources of a further spread of the virus.

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