With 108 new cases recorded in Victoria on Saturday and an outbreak in the crowded inner-city social housing towers, Premier Daniel Andrews has forbidden 3000 residents from leaving their apartments for any reason.

Mr Andrews on Saturday announced police would enforce the lockdown of the North Melbourne and Flemington estates and that food and other supplies would be delivered to them.

Within minutes of the premier's announcements, police swarmed the housing estates, blocking entrances.

All other residents in the postcodes where the towers are located will be under stay-at-home orders by 11.59pm on Saturday, as postcodes 3031 and 3051 were added to the 10 existing community transmission "hot zones".

The peak body for the social service sector said any mistakes in the management of the public housing lockdowns could be "horrific".

Residents there are dealing with trauma from war and domestic violence, mental illness, disability, difficulty with English and unreliable employment, Victorian Council of Social Services head Emma King said.

They must be treated sensitively and be given access to support services and information.

Australian Greens leader Adam Bandt, whose federal electorate covers some of the estates, said his office had been alerted to a lack of pandemic information in the buildings and had approached the health department in March about getting mailroom access to post leaflets in 13 different languages.

The department's response, obtained by AAP, says its social distancing policy made it impossible to access the building and recommended sending information via Australia Post.

Mr Bandt did this but did not have the funds to mail everyone.

Shadow health minister for Victoria Georgie Crozier said the potential for family violence over the next five days was "very real".

Shadow housing minister Tim Smith said police should be accompanied by translators, doctors, community leaders, and drug and alcohol counsellors.

Flemington housing resident Hoda God, 31, told AAP families in her building were struggling as soon as police enforced the lockdown.

A woman with three children was barred from going out to buy formula for her baby and another woman with a five-year-old was not allowed out to buy groceries for dinner, she said.

"They need groceries now," she said. "She has nothing to cook tonight."

Deputy chief medical officer Annaliese van Diemen attributed an outbreak of up to 30 cases across the public housing towers to close-quarters living and shared spaces.

Health workers will go door-to-door doing virus tests and Mr Andrews warned that rejecting a test could mean the hard lockdown runs longer.

The 108-case jump is the second biggest COVID-19 increase recorded in Victoria since the start of the pandemic.

There are 509 active cases with 25 people in hospital, including three in intensive care.

Of the 108 new cases, 69 are under investigation, 14 are from known outbreaks and 25 from routine testing.

"If we don't all follow the rules, every postcode will be locked down," Mr Andrews said.

Federal Acting Chief Medical Officer Paul Kelly has called an emergency meeting of medical officers across the country to discuss the Victorian situation.

Australian Associated Press