The announcement came after the state recorded 12 new locally acquired cases of COVID-19 overnight, bringing the total number of active cases 34.

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Mr Merlino said the cluster linked to the hotel quarantine breach had grown to 26, with one person in intensive care and on a ventilator.

"In the last day, we've seen more evidence we're dealing with a highly infectious strain of the virus, a variant of concern, which is running faster than we have ever recorded," he said.

"From first thing (Thursday morning), we have identified in excess of 10,000 primary and secondary contacts who will need to either quarantine, or test and isolate, and that number will continue to grow and change."

Related: What the new coronavirus restrictions mean for me?

From Friday, vaccinations at state sites will be expanded to include those in the 40 to 49-year-old age group, for the Pfizer vaccine.

"We were looking at how we can expand the eligibility for vaccinations. And we've been doing that work and we've got advice from public health, and from the Department of Health," Mr Merlino said.

"From tomorrow morning, vaccinations at state sites will be expanded to include those in the 40 to 49-year-old age group, for the Pfizer vaccine.

"In terms of GPs, that will be a decision of the Commonwealth, but in terms of the state sites that we run, we'll be expanding it to 40 to 49."

More news:

Victorians will once again only be able to leave their homes for five permitted reasons: shopping for essential items, essential work, exercise for two hours a day, caregiving for compassionate reasons and to get vaccinated.

Other restrictions include compulsory masks in all settings outside the home, a 5km radius ban on movement, and a ban on all private gatherings.

Venues to close include schools and universities, which will transition to home-learning, as well as hairdressing and beauty services and sport and recreational venues.

Hospitality will move to takeaway only.

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Essential retail stores will remain open including supermarkets, food stores, bottle shops, pharmacists, banks and petrol stations.

Other retail stores can provide click and collect.

Childcare and kindergartens will remain open and real estate auctions will only be held online.

No visitors will be permitted except for very limited reasons and will be allowed at aged care facilities.

In hospitals, visitors will only be permitted for end of life care, support for a partner during birth or a parent accompanying a child.

For funerals a maximum of 10 people plus those running the service and weddings will not be permitted unless end of life or deportation reasons apply.

Religious activities will not proceed other than through broadcast with a maximum of five people.

Other news:

As of Thursday morning, there were 79 exposure sites listed on the Health Department's website, spread across more than 30 Melbourne suburbs and Bendigo, Axedale, Cohuna and Red Hill.

A Bendigo Health spokeswoman said about 400 people were vaccinated in Bendigo on Monday and about 500 people were tested on Tuesday.

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