Authorities remain concerned as the virus continues to spread rapidly across metropolitan Melbourne despite tough lockdown measures.
Covid-19 commander Jeroen Weimar said there had been a shift toward the southeast regions of the city in the past 10 days with infections rising to their highest level in Casey on Sunday.
He said half of the cases were from six local government areas – Brimbank, Casey, Hume, Melton, Whittlesea and Wyndham.
"With only 50 per cent of those cases in the six LGA areas, it means there's a lot of cases across other parts of Melbourne and regional Victoria," he said.
Lockdown is set to end in Victoria around October 26 when 70 per cent of Victorians aged 16 and older are fully vaccinated.
As of Saturday, 86.1 per cent of Victorians aged 16 and over had at least one dose of a Covid-19 vaccine and 58.1 per cent were fully vaccinated.
Premier Daniel Andrews has committed to ending the lockdown as planned when the state reached 70 per cent fully vaccinated.
There are 19,012 active coronavirus cases in Victoria, with more than 12,000 cases in the last week alone.