From Thursday, residents in metropolitan Melbourne and Mitchell Shire, north of the city, will be forced back into stage three lockdown as part of efforts to contain a second wave of coronavirus.

Victoria recorded 134 new cases of COVID-19 on Wednesday, its second-highest single-day total after a record 191 cases on Tuesday.

More than 850 cases remain active, an increase of nearly 800 in a month.

Premier Daniel Andrews said it was imperative no one breaches restrictions and ventures into regional Victoria, which has largely remained free of coronavirus.

"We are doing the hard work to look at options to accelerate opening up in regional Victoria, that comes with significant economic benefit, for them and therefore the whole state," he told reporters on Wednesday.

"That is only possible if we continue to safeguard the very low COVID or COVID-free status of large parts of regional and country Victoria."

Chief Commissioner Shane Patton 700 police officers and 264 members of the Australian Defence Force will enforce the lockdown, with booze bus-type checks in place on main roads in and out of the city, and number plate recognition technology used.

"We're going to be checking people. We're going to be making sure they're adhering to those guidelines," he said.

"If you don't have a reason to leave, you will be turned back around."

He said on-the-spot fines of up to $1652 will be handed out to people caught breaching lockdown rules, while businesses could be fined $9913.

"We've done this before in restrictions we've been through. People know what to do. They know what to expect," Mr Patton said.

Police have done 92,215 random checks since March to ensure people were at home and businesses were abiding by the rules.

Residents in the lockdown areas will only be able to leave their homes to get food and supplies, receive or provide care, exercise, and study or work.

Victoria now has a total of 2942 cases.

Testing has revealed infection protocol breaches by security guards working in hotel quarantine fuelled the second wave of the virus in the state.

Mr Andrews said those to blame are "no longer playing a part in our hotel quarantine arrangements".

Of the state's new cases, just 11 are linked to known outbreaks while 123 remain under investigation.

They include four patients and a worker at Brunswick Private Hospital, which is now closed to new admissions while contact tracing is under way.

Another Ambulance Victoria paramedic has coronavirus, bringing the total number to test positive since the start of the pandemic to five.

The paramedic is a close contact of one of the paramedics who returned a positive result on Tuesday.

Five positive cases have also been linked to aged care services across the state.

Meanwhile, cases linked to the nine public housing towers in Flemington and North Melbourne in hard lockdown have slowed to two new infections on Wednesday, with the cluster now totalling 75.

Testing of all 3000 residents is expected to be completed soon.

One million Victorians have been tested for COVID-19 since the start of the year, with a record of 29,424 tests conducted on Tuesday.

The premier said further announcements will also be made regarding economic support, after modelling showed the lockdown would cost the state about $1 billion per week.

"We have to get past this public health bushfire and get back into a position where we can start to open up again and start to repair the very significant economic damage," Mr Andrews said.

To date, 22 Victorians have died from the virus while 41 remain in hospital.

Australian Associated Press