Victoria has recorded five new locally acquired cases of coronavirus as the state endures its second day of a seven-day snap lockdown.

Four of the new cases are close contacts of a food delivery driver who travelled across north and southeast Melbourne while potentially infectious.

But the state’s health minister believes authorities are “getting close on the heels” of the outbreak as more exposure sites are revealed.

The new cases were detected from 56,624 test results processed on Friday, a record for the state.

There are now 45 active cases of COVID-19 in Victoria, which includes another two recorded in hotel quarantine.

Tweet from @VicGovDH

Most infections are linked to the City of Whittlesea cluster in Melbourne, with cases testing positive for the B1617 strain first identified in India.

Health Minister Martin Foley told reporters four of the five local cases on Friday were connected to a delivery driver earlier confirmed COVID-positive who worked for numerous days while infectious.

“They either live in the same household or there was a meeting of households, quite appropriately, where transmission occurred … (and) one of those is a student at Mount Ridley College (in Craigieburn),” he said.

The final case was a person connected to the Port of Melbourne outbreak linked to Stratton Financial. A worker at the financial firm visited a Mickelham display home and infected a worker there, Mr Foley said.

At least 14 Stratton employees are now COVID-positive.

While refusing to speculate on an extended lockdown, Mr Foley said he was confident authorities were bringing the issue under control.

He said close contacts of cases who visited Highpoint shopping centre in northwest Melbourne and two AFL games were returning negative results.

“We do not know what is in store in the next 24 hours but are making exceptional progress in terms of contact tracing and we are, I think, getting close on the heels of this outbreak,” Mr Foley said.

Victoria’s latest lockdown will last until at least Friday.

The fourth in 15 months, the lockdown has again sparked rallies protesting the tough restrictions.

At least 10 people were arrested at a march in Melbourne’s Flagstaff Gardens on Saturday.

But Mr Foley said the government would not change tack.

“The virus does not respond to protests,” he said.

Chief Health Officer Brett Sutton on Friday said the restrictions were necessary.

“We absolutely have to recognise that there are thousands and thousands of close contacts that are still to go through the incubation period who could become symptomatic,” he said.

Victorians have been told not to leave home except to shop for food and essential items, to provide or receive care, for exercise, work or study, or to get vaccinated.

People must observe a five-kilometre travel limit for exercise and shopping, and wear masks both indoors and outdoors.

Victoria’s testing commander Jeroen Weimar said on Saturday hundreds of pub-goers had been forced into isolation after being exposed to COVID-19.

There are five pubs and clubs that have been identified as areas of concern, including Three Monkeys in Prahran, Somewhere Bar in Prahran, The Palace Hotel in South Melbourne, The Local in Port Melbourne and The Sporting Globe in Mordialloc.

So far officials have identified 500 close contacts across those venues.

“Just under 20 per cent of those have returned a negative test result and I’m expecting to see negative results coming in over the next few days for those 500 primary close contacts,” Mr Weimar said.

A patron at The Sporting Globe in Mordialloc contracted the virus while at the venue with an infected person on the evening of May 23.

Saturday is Victoria’s second day of statewide lockdown to respond to the outbreak. Photo: ABC News/Patrick Rocca

Scores of Melburnians queuing to be vaccinated are facing an enormous wait after technical issues crippled the vaccine booking systems and forced hubs to open late.

Some walk-ins reported being turned away from vaccine centres and others said they’d been told delays had stretched to five hours.

It comes after the state’s coronavirus hotline was flooded with more than 77,000 calls in 15 minutes when it was announced on Thursday eligibility for the Pfizer vaccine would be expanded to people aged 40-49.

The Victoria Department of Health’s Jeroen Weimar said the state was unable to administer more than roughly 20,000 jabs a day and booking system issues would be addressed by new software.

The issues came as more than 15,000 primary and secondary contacts were been told to self-isolate after coming into contact with a COVID case.

The state government has asked for 160 defence force personnel to help check on the thousands of people who have been told to isolate at home.

The list of exposure sites had grown by Saturday to more than 150, including a flu vaccination centre in the suburb of Preston.

The state’s coronavirus hotline was flooded with more than 77,000 calls in 15 minutes when it was announced on Thursday that eligibility for the Pfizer COVID-19 vaccine would be opened up to people aged 40-49.

Some 10,000 bookings were confirmed on Thursday, while more than 2000 bookings were made before 9am on Friday.

People struggling to get through were urged to call back later, rather than turning up at mass vaccination centres.

More staff have been assigned to answer calls, while work is underway on an online booking system.

It’s estimated the lockdown will cost the state’s economy about $2.5 billion.

-with AAP