Andrews announced the “circuit-breaker” was necessary to contain the Holiday Inn coronavirus outbreak, which now totals 13 cases, confirming the state will enter “stage four” restrictions at 11.59pm tonight.

People will only be able to leave their homes to shop for food and essential items, to provide or receive care, exercise, and work and study if they can’t from home.

The 5km limit on travel will also be reimposed, as will the compulsory use of masks both indoors and outdoors.

All non-essential retail will close but supermarkets, bottle shops and pharmacies will remain open. Cafes and restaurants will only be able to offer take-away.

Weddings will not be permitted unless under exceptional circumstances, while funerals will be restricted to 10 mourners.

Andrews said the UK strain of the virus is “so hyper-infectious and moves so fast that it is presenting a very real challenge” for authorities.

“It is the advice to me that we must assume that there are further cases in the community than we have positive results for, and that 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.

“We are having cases test positive, and we in rapid time get notified of that positive test result … they’ve already infected their close contacts, their family, people they live with – and that makes it incredibly difficult to do contact tracing.

“If we wait for this theory that it (the virus) might be out there… it will be too late.”

The Australian Open tennis tournament will continue without crowds, with Andrews saying it would “function essentially as a workplace”.

“But they will not function as an entertainment event because there will be no crowds and the workplace will be the minimum that is needed in order for that to be COVID-safe,” he said.

The AFLW this morning suspended ticket sales for Round 3 but has been reported to be pushing ahead with its schedule, with fixtures in Victoria this weekend likewise to be played with no crowds.

Saturday’s A-League match between Western United and Sydney FC in Melbourne has been postponed.

Victoria recorded five new COVID-19 cases on Friday, all of which are connected to the Holiday Inn at Melbourne Airport.

The new cases include a female assistant manager and four close contacts of people who earlier tested positive to COVID-19.

The whole of Melbourne Airport’s Terminal 4 has been listed as an exposure site after a case worked at Brunetti cafe on February 9 between 4.45am and 1.15pm.

Anyone who visited the terminal during that time needs to get a COVID-19 test and isolate for 14 days, including those who have since travelled interstate.

Melbourne Airport confirmed to The Age this morning that 29 domestic flights departed and landed at Terminal 4 during this period.

There was at least one flight from Melbourne Terminal 4 to Adelaide Airport on February 9 – JetStar Flight 778 – although it departed around 9 pm (AEDT).

NSW Health is currently following up around 7000 travellers who entered NSW from Melbourne Airport Terminal 4 on February 9, or who attended any terminal at the airport on February 7 and 8.

Victoria Health says anyone who visited the Brunetti cafe during the exposure time needs to get a COVID-19 test and isolate for 14 days.

It brings the total number of exposure sites listed on the Health Department’s website to 30.

There are now 19 active cases in total in Victoria, with more than 24,000 tests conducted on Thursday.

Speaking at a CSL facility in Melbourne before the announcement, Prime Minister Scott Morrison said he had not yet been briefed by the Victorian government but noted hotel quarantine workers have also contracted the virus in Adelaide, Brisbane, Perth and Sydney, sparking short lockdowns in those cities.

“We have dealt with these before, got on top of them before,” Morrison told reporters.

“A proportionate response that enables the (contact) tracers and others, to be able to get on top of it and get the same successful result we have seen in other states – that can and will be achieved here.”

Morrison said he understood Melburnians did not want to endure another long lockdown.

“As other states have demonstrated, you can get on top of this pretty quickly, and I have reason for confidence that they can do the same thing by following that same process,” he said.

Victoria’s COVID-19 response commander Jeroen Weimar said yesterday authorities were “right on top” of the outbreak, picking up cases among identified contacts who had tested negative just days earlier.

His “working assumption” is all the cases have been infected with the more transmissible UK variant of COVID-19, complicating the containment job.

“This is by no means over,” Weimar said.

“We are still in the opening quarter of the Holiday Inn outbreak, I’m afraid. We’ve got a lot more work to do.”

South Australia locked out travellers from the Victorian capital at midnight on Thursday, while Queensland will bar entry to visitors of the city’s exposure sites from 1am on Saturday.

Western Australia also announced its hard border to Victoria would be extended for at least another seven days.

An undeclared nebuliser, used inside the room of an infected family of three at the hotel, is the suspected cause of the outbreak.

SA Premier Steven Marshall will hold a media conference at 3:15pm.

-Staff writers with AAP