Victoria has recorded four new locally acquired cases of coronavirus on the first day of its seven-day, statewide lockdown.
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 was 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.
The lockdown is set to end at 11.59pm on June 3, although the acting premier has flagged it could end earlier.
People can only leave home for five reasons: to shop for food and essential items, to provide or receive care, for exercise, work or study, or to get vaccinated.
Victorians must observe a five-kilometre travel limit for exercise and shopping, and compulsory wearing of masks both indoors and outdoors.
All non-essential shops are closed but essential stores such as supermarkets, bottle shops and pharmacies remain open, with shopping limited to one person per day, per household.
Cafes and restaurants can only offer takeaway.
Childcare and kindergarten facilities will stay open but schools are going back to remote learning for most students. State-run schools are having a pupil-free day on Friday to prepare for the switch.
The lockdown is expected to cost Victorian businesses up to $1 billion.