Victoria will enter a five-day lockdown from midnight to contain an outbreak linked to the Holiday Inn hotel, which now totals 13 cases.

Premier Steven Marshall this afternoon confirmed a raft of new restrictions, with South Australians who have recently travelled to SA via Melbourne’s main airport, Tullamarine, also urged to get tested.

“From today, the 12^th of February, transit through Tullamarine airport to SA will no longer be permitted,” Marshall told reporters.

“People who have been to Terminal 4 from [Tuesday] February 9 must quarantine for 14 days from the date of arrival.”

Family and close contacts must similarly quarantine until they obtain a negative COVID test.

SA authorities are trying to contact around 500 people likely to be affected by this quarantine order.

Further, anyone who has been at Tullamarine from Sunday, February 7 – along with their families – must urgently get tested and isolate until they get a negative result.

Marshall said border restrictions imposed on Greater Melbourne earlier this week – with only returning residents and limited other exemptions allowed to enter SA if they quarantine for a fortnight – would now be extended to the state of Victoria from midnight tonight, lasting at least for the duration of the lockdown.

“This also includes the cross-border arrangements whilst Victoria has its Stage 4 lockdown,” the Premier said.

Police Commissioner Grant Stevens said cross-border residents in Victoria “are bound by the Victorian State Government direction”.

“Those residents must abide by the restrictions imposed on the whole state,” he said, but noted that state’s exemptions, including travel for medical purposes, essential work or shopping would be allowed to enter SA where relevant.

SA chief public health officer Professor Nicola Spurrier said: “Obviously things are progressing quite rapidly in Victoria.”

“This is the variant of concern,” she said of the UK B117 COVID strain whose outbreak has prompted the new lockdown.

She said SA had been briefed about two Tullamarine workers that were close contacts of cases at the Holiday Inn quarantine facility, which spawned the latest cluster.

One of the two worked at a Terminal 4 café, “where Jetstar flights and Rex flights leave from”, and is believed to have worked an 8.5 hour shift whilst infectious.

“There are national guidelines for masks in airports, but if you go to get a coffee you’ll be drinking your coffee with your mask off,” she said.

“We’re requiring anybody that’s been at that terminal on the 9^th and subsequently to quarantine.”

A Tullamarine cleaner also tested positive, but while “that person has [visited] a larger number of areas that are potential exposure sites”, they were “considered to be of lower infectiousness” at the time.

Marshall said “our thoughts are with our friends in Victoria”.

“Lockdowns are difficult for everybody – we’ll be doing anything we can to work with Victorian authorities to offer them anything they might need,” he said.

Spurrier said forthcoming Adelaide events, including the Fringe and the Adelaide International tennis tournament, would be assessed.

“We’re looking on a case-by-case basis – if we’re not able to give exemptions, those festivities will need to be cancelled,” she warned.

“My team is working through what that means… we want to retain events as much as we possibly can, but we need to make it as safe as possible in SA.”

However, she said SA was in “a good position because we’d already put out border [restrictions] in place very early”.

Earlier today Victorian Premier Daniel Andrews confirmed that state will enter a five-day “circuit breaker”, with residents only able to leave home to shop for food and essential items, provide or receive care, exercise and to work or study if they can’t from home.

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

As with stage four restrictions, 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.

The Australian Open tennis tournament, as well as the AFLW and other sporting events, will continue without crowds.

Andrews said the UK strain of the virus was “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 told reporters.

“I am confident that this short, sharp circuit breaker will be effective. We will be able to smother this. We will be able to prevent it getting away from us.”