A man and woman in their 80s and a man in his 70s have died, bringing total COVID-19 deaths to 32 in the state and 116 nationwide.

Chief Health Officer Brett Sutton's cautious optimism on Thursday was gone, replaced by worry about Friday's deaths and the dramatic increase in new case numbers.

The previous record was Victoria's 317 on Thursday.

"Certainly 428 new cases is both disappointing and concerning," he said

"We have not turned the corner here."

There has been growing concern through the week that if Victoria's numbers do not stabilise, the state might have to introduce stricter lockdown measures.

Professor Sutton said he hoped numbers would start to stabilise, but more hospitalisations were inevitable with such large daily case numbers.

"There will be dozens of individuals who require hospitalisation out of these 428 people," he said.

"Tragically, there will be several who require intensive care support, and a number of people will die, and whenever we have a day with these numbers that is the case, so it has to turn around."

Friday's increase puts Victoria at its 12th straight day of triple-digit figures, which Prof Sutton said reflects behaviours and mobility from 10 or more days ago.

"There's a hope that these numbers stabilise in the coming days towards the end of this week. That's my hope," he said.

"But no one is being complacent here ... we have to bear in mind any additional measures that are important to help control the numbers."

Of the 5165 cases across the state, 122 people are in hospital with 31 of them in intensive care.

A male prisoner at the Melbourne Remand Centre is among the latest confirmed cases, with the Department of Justice and Community Safety confirming the positive test result on Friday.

He is now in isolation and contact tracing and thorough cleaning are underway, a spokesperson said.

It is understood this case is considered a low risk of transmitting the virus.

Prof Sutton confirmed one of the latest deaths was the second to be linked to an outbreak at Menarock Aged Care in Essendon.

All 15 remaining residents at Menarock will be transferred to hospital, the federal government announced on Friday.

Aged care homes have had a rapid increase in infections during the second outbreak, with new cases recorded at care homes in Brighton, Plenty, Greensborough, Werribee and Sunshine.

There are 160 cases linked to the Al-Taqwa College outbreak, 51 cases to Somerville Retail Services in Tottenham and 32 cases connected to JBS abattoir in Brooklyn.

Prof Sutton said the Alfred Street public housing tower in North Melbourne, which is under a hard lockdown, had about 20 additional cases, bringing it to about 70 in total.

Victorian Ombudsman Deborah Glass has launched an investigation into the hard lockdown at 33 Alfred St, after more than 50 people contacted her office concerned about the treatment of residents.

Meanwhile, Premier Daniel Andrews announced coronavirus testing would further ramp up across the state with five new sites to be set up in regional Victoria.

The regional testing sites will be established in Echuca, Wonthaggi, Bendigo, Shepparton, Koo Wee Rup and Mildura.

The premier also issued a directive for regional Victoria that if people in those areas are unable to socially distance from others they should wear a mask.

The government has also clarified some of its messaging around exercise for those in locked-down areas.

Under stage three restrictions people are only allowed to leave their homes to buy food and supplies, for care and caregiving, to go to work or study if they cannot do so from home, and to exercise.

Mr Andrews confirmed that people cannot travel for exercise, citing an incident where a group had travelled from Coburg to the Mornington Peninsula.

"That is a 200km round trip, that is not daily exercise. That is a day trip and day trips are not on," he said.

Australian Associated Press