The Australian state of Victoria will go into a snap lockdown from tonight in response to a growing coronavirus cluster.
Victorian Premier Daniel Andrews announced this afternoon a five-day "circuit-breaker" lockdown for the entire state would go into effect from 11.59pm tonight (local time).
Andrews said the lockdown was needed because some of the new cases had the UK strain, which was "hyper-infectious" and posed a huge challenge to the state.
He said it was very difficult to do effective contact tracing due to the "speed at which this UK variant moves".
"If we wait for this theory that it might be out there, that there might be more cases, it might be too late."
Victorians will only be allowed to leave their homes for limited reasons: essential supplies, care and caregiving, and exercise and essential work. No visitors are allowed. Exercise and shopping will be limited to 5km from people's homes.
Masks must be worn in all public spaces. Retailers will close, with exceptions for essential businesses, and public gatherings will not be permitted. Schools and places of worship will close.
The Australian Open tennis tournament in Melbourne will continue but without crowds. No fans will be allowed at Melbourne Park to watch the tennis for the next five days.
Andrews said health officials now predict that there are further undetected cases in the community.
"I know it's not the place that we wanted to be in," he said. "However, we've all given so much, we've all done so much. We've built something precious, and we have to make difficult decisions, and do difficult things, in order to defend what we've built.
"I am confident that this short, sharp circuit-breaker will be effective.
"I want to be here on Wednesday next week announcing that these restrictions are coming off, but I can't do it on my own. I need every single Victorian to work with me, and with our team, so that we can run this to ground and we can see this strategy work."
He said the UK varient was posing huge problems to the contact tracing effort.
"It is moving at a velocity that has not been seen anywhere in our country over the course of these last 12 months," he said.
It will be the state's third lockdown since the start of the pandemic.
It is understood that state government advisers met overnight to draw up a framework for another lockdown as a Covid cluster linked to Melbourne's Holiday Inn MIQ facility grew overnight to 13 cases.
The state's Cabinet met for an emergency meeting at 11.45am. At the same time, federal senators who are based in Melbourne were heading to Canberra.
Authorities are not only concerned about the Holiday Inn cluster, but also about virus fragments detected in wastewater across Melbourne.
A source close to Emergency Management Victoria told the Herald Sun earlier today authorities feared they had lost control of the outbreak — describing scenes of "pandemonium" at the agency.
They told the newspaper there were deep concerns at the failure of contact tracers to match information they had been given by confirmed cases and their close contacts with what the results of sewage testing were showing about the virus' spread.
Officials are working with the theory that all of the cases linked to the Holiday Inn outbreak are UK strain cases — meaning it could spread a lot more quickly than the strain that took hold of Victoria last year.
Prime Minister Scott Morrison told 3AW earlier today the Victorian Government was looking at all options.
The Prime Minister said that the traumatising impact of the lockdowns on Victorians was very "real" and he understood why it was upsetting news that the option was on the table.
But he suggested a short, sharp lockdown had worked in the past interstate to give contact tracers a head start.
"The short, sharp proportionate response that we saw in other states proved to be quite effective. We saw that work in Brisbane. It worked in NSW."
Other states respond
State and territory leaders across Australia have hardened border measures to prevent Victoria's outbreak from spreading interstate.
Western Australia, Queensland, Tasmania, the Northern Territory and the Australian Capital Territory all moved to change travel rules on Friday as Victoria entered a strict five-day lockdown.
From 6pm Friday, WA will introduce a hard border with Victoria for 72 hours, meaning no one can enter the state, Premier Mark McGowan said.
Queensland will also close its border to Melbourne from 1am Saturday.
Melbourne will be declared a hotspot for 14 days and anyone from 36 local government areas around the city will not be allowed to enter the Sunshine State.
Officials in the Northern Territory have also declared Melbourne, and Tullamarine Airport, a Covid hotspot.
This means anyone arriving in the Top End, effective immediately, must isolate at the Howard Spring quarantine facility or take the first return flight home.
Anyone who is already in the Northern Territory and has been in Melbourne, including the airport, since February 7 must self-isolate until they receive a negative result.
From midnight Friday Tasmania will shut its border to Victorians.
Tasmanian residents will be allowed to return home but must self-quarantine for 14 days.
The ACT will introduce travel restrictions with Victoria from midnight.
The territory's chief health officer Dr Kerryn Coleman said residents in Victoria should stay there and take part in the five-day lockdown.
Any ACT residents who returns home before midnight does not not need to quarantine but should get tested if they experience any symptoms.
If they return after midnight Friday they will need to self-quarantine for five days, in line with Victoria's snap lockdown.