Acting Premier James Merlino confirmed the new cases are linked to the City of Whittlesea cluster, which now stands at 30 cases. There were also two new cases in hotel quarantine, bringing the total number of active cases in the state to 39.
A record 47,462 Victorians were tested in the 24 hours to Friday morning, while 17,223 received a dose of the COVID-19 vaccine.
"This is exactly the sort of numbers we want to see each and every day," Mr Merlino said.
The state's COVID-19 Testing Commander Jeroen Weimar said 15,000 people were self-isolating after coming into contact with COVID-positive cases. Some 1452 are considered primary close contacts.
There are more than 150 exposure sites across Melbourne and regional Victoria.
Mr Weimar said authorities were particularly concerned about five sites - the Sporting Globe in Mordialloc, Three Monkeys and Somewhere Bar in Prahran, Palace Hotel in South Melbourne and The Local in Port Melbourne.
"They are ... places where we expect to see significant numbers of people in close proximity, dancing, singing, doing what they do," he said.
One person caught the virus at the Sporting Globe in Mordialloc, making it the first case of community transmission in the outbreak.
Mr Merlino also revealed he would get the Pfizer COVID-19 vaccine later on Friday after the state opened up eligibility to Victorians aged 40 to 49.
He said there was incredible demand for the vaccine in that age group, with the state's coronavirus hotline inundated with calls immediately after it was announced vaccination eligibility would be broadened.
More than 77,000 calls flooded the hotline in a 15-minute window on Thursday before "technical issues" were resolved.
Mr Weimer said 10,000 bookings were confirmed on Thursday, while more than 2000 bookings before 9am on Friday.
"A couple of days ago we had 350 people working on vaccination bookings and today we have over 550 working on vaccination bookings," he told reporters.
Mr Weimar said there were also plans to create a website for vaccine bookings.
The lockdown is set to end at 11.59pm on June 3, although the acting premier has flagged it could end earlier.
The lockdown is expected to cost Victorian businesses up to $1 billion.
Federal Health Minister Greg Hunt on Friday confirmed the Commonwealth would not provide any financial support to affected businesses.
"At this stage, Victoria is the responsible body they have said that they will be providing additional support," Mr Hunt told ABC Radio National.
"This is a difficult time, and I'll leave those matters to the treasurer, but the Victorian government has indicated that they will be taking those measures."
The ABC is reporting the state government will announce a $200 million package to support small businesses in Victoria.