From 11:59 p.m. on Thursday local time until June 3, the state’s seven million residents will be urged to stay in their homes except for essential jobs, health care, shopping and exercise. .
This comes just days after the return of the other rules – limits on collection sizes and mandatory face masks in restaurants, hotels and other indoor locations until June 4.
Acting Prime Minister James Merlino said: “We are dealing with a highly infectious strain of the virus, a worrying variant, which is working faster than we have ever recorded.
“Unless something drastic happens, it will get more and more out of control. “
The number of reported cases in the state rose to 34 after 12 new cases overnight, with the number of sites exposed to the virus surpassing 150.
The source of the latest outbreak is a Victorian man who tested positive for the variant first reported in India.
He completed the mandatory hotel quarantine in South Australia before heading to Melbourne, where he tested positive six days later.
Mr Merlino said more than 10,000 primary and secondary contacts had been identified who would need testing and isolation, but he said that number is expected to increase.
Several of those infected have visited crowded places before being contacted, such as sports stadiums and shopping malls.
Western Australia, South Australia and Tasmania have closed their borders to residents of Victoria, while the Northern Territory and Queensland will enforce a mandatory two-week hotel quarantine for arrivals.
New South Wales has asked residents to postpone non-emergency travel to Victoria and New Zealand is expected to make an announcement later on the future of the travel bubble with Melbourne.
The outbreak is the first in Victoria for more than three months.
The state carried out a long and strict lockdown last year to tackle an outbreak that has killed more than 800 people – 90% of total COVID-19 deaths in Australia.
Overall, Australia has recorded just over 30,000 cases and 910 deaths, but its vaccination rate has been very slow – only 1.7% of the population is fully vaccinated.