VICTORIA will enter a seven-day lockdown in a bid to curb the state's growing coronavirus outbreak.
There are 34 active cases of coronavirus in Victoria, with 26 linked to the hotel quarantine breach in South Australia.
One is in intensive care on a ventilator.
Health Minister Martin Foley said the person in ICU was "an elderly person" who was among the earlier cases in the outbreak.
Acting Premier James Merlino said more than 10,000 primary and secondary contacts were linked to the outbreak, a number that will "continue to grow and change".
"The number of cases has doubled in that last 24 hours," he said. "Unless something drastic happens, this will become increasingly uncontrollable.
"If we make the wrong choice now, if we wait too long, this thing will get away from us."
The circuit-breaker lockdown will be in place until 11:59pm on June 3.
Mr Merlino said there would be only five reasons people would be allowed to leave their homes:
- Food and supplies
- Authorised work
- Care and caregiving
- Exercise for up to two hours with one other person
- Getting vaccinated
Schools will close for the duration of the lockdown, but childcare and kindergartens will be open.
Mr Merlino, whose main portfolio has been education, said he had instructed his department to set tomorrow aside as a pupil-free day to help schools prepare for remote learning next week.
Cafes and restaurants can offer take-away only, and public and private gatherings will not be allowed.
People will have to restrict their exercise and shopping to within five kilometres of their homes, and masks must be worn everywhere outside of the home unless a person has an exemption.
No visitors will be allowed other than intimate partners.
A full list of the restrictions can be found on the government's website.
Concern over new virus strain
Minister Merlino said public health experts' prime concern was just how fast the B1.617.1 variant is moving.
"The time between catching the virus and passing it on is tighter than ever," he said.
"The 'serial interval' - how long it takes between the onset of symptoms in the first and secondary case - is in many cases just over a day.
"And in just 24 hours, the number of cases has doubled.
"It means that although these cases are all connected, this variant of the virus is making people more infectious, more quickly."
He said the nation's vaccine rollout has been slower than hoped.
"We would not be in this position that we are today - this necessary and difficult position - if our vaccination rates were much higher than they are right now.
"I really encourage everyone, if you're eligible, get vaccinated.
"It's clear - more than ever - this virus isn't going away. And vaccines are the only way we'll ever get back to normal.
"Without full vaccination, this virus will just keep mutating - and just keep making its way back in."
The Pfizer vaccine rollout has been expanded to those in the 40 to 49-year-old age group.
Victoria's Chief Health Officer, Brett Sutton, said it was "very reassuring" that all of the newly-diagnosed cases were linked.
"We know where transmission occurred," he said.
"There's the workplace that's been identified and all of the others are the related households and casual links for the City of Whittlesea outbreak.
"So that's very reassuring, that's great work again of contact tracing, but it's also about people giving very detailed information about where they've been so that we can make those links appropriately."
Victoria records 12 new COVID-19 cases overnight
Earlier, 9am: There were 12 new locally acquired cases of COVID-19 detected in the state overnight.
This brings the total number of active cases across the state to 34.
Authorities administered more than 12,500vaccinations on Wednesday with another 40,411 people who got tested for the virus.
The list of COVID-19 exposure sites grew on Wednesday and now include venues in Bendigo, Axedale and Cohuna.
As of Thursday morning, there were 79 exposure sites listed on the Health Department's website, spread across more than 30 Melbourne suburbs and regional Bendigo, Cohuna and Red Hill.
The MCG and Marvel Stadium are amongst the exposure sites and three inner- suburban nightclubs remain a "concern".
An infected person attended the Collingwood-Port Adelaide AFL game at the MCG on Sunday, while one was also at the North Melbourne-Essendon clash at Marvel Stadium later that same day.
A decision on crowd limits for this weekend's AFL matches in Melbourne has been delayed and the RISING festival has been cleared to go ahead, for now.
A number of restrictions were introduced for Greater Melbourne on Tuesday evening, including gathering limits of five people at homes and 30 in public and mandatory masks indoors.
Genomic sequencing shows the City of Whittlesea outbreak is linked to the case of a Wollert man, who contracted the virus in quarantine in South Australia earlier this month.
A report released on Wednesday in SA found it likely he caught the virus through aerosol transmission due to the "timing of doors opening and closing" at an adjacent room occupied by an infected guest.
SA on Wednesday became the first state to close its border to residents of Greater Melbourne. NSW and Queensland are urging residents to reconsider travel to the city and parts of regional Victoria.
Victoria's last lockdown was for five days in February, after the virus escaped hotel quarantine and infected 13 people.
It was the state's third lockdown since the coronavirus pandemic began last year.
Australian Associated Press
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