Victoria has recorded three new locally acquired coronavirus cases as the list of exposure sites grew to more than 50 venues across multiple towns and Melbourne suburbs.

The new infections were detected from 22,477 test results processed on Saturday.

All three new cases are connected to a cluster at the Smile Buffalo Thai restaurant in Black Rock, bringing the total number of COVID-19 infections linked to the restaurant to 21.

Authorities confirmed on Saturday the cluster was “directly linked” through genomic sequencing to the outbreak in New South Wales.

Deputy Chief Health Officer Allen Cheng said 13 of the cases dined at the restaurant on December 21.

“The other eight cases are all linked, either directly or indirectly, basically through family gatherings at Christmas,” Professor Cheng said.

He said there were about 220 close contacts in 14-day quarantine and about 360 secondary contacts.

“With this number of close contacts, we are expecting at least some of them may become case over the next week or so,” he said, adding the risk of transmission was reduced because they were quarantining already.

A woman gets a coronavirus test in her car.
People have waited hours to be tested as Victoria works to get on top of the latest outbreak.(ABC News: Chris Le Page)

The health department’s list of exposure sites is updated regularly but was again expanded on Sunday to include a nail salon and dumpling restaurant in Camberwell, a cafe in Albert Park and a V/Line train from Bairnsdale to Melbourne.

The Chants Summer Carnival in Lakes Entrance, Gippsland, was also added to the list.

By Sunday afternoon, there were 51 venues listed.

“That is a significant number of exposure sites,” Department of Health and Human Services (DHHS) COVID-19 response commander Jeroen Weimar said.

“And of course it highlights that with the 21 cases in this cluster at the moment, that people do, rightly, travel around quite extensively at this time of year.”

Depending on the level of risk allocated to the venue, people who attended the exposure sites are asked to quarantine for 14 days, isolate until receiving a negative result, or monitor for symptoms.

Long lines at testing sites for the third day in a row meant hours-long waits for many, and there were again reports of people being turned away at testing centres.

A traffic warden in an orange high-vis shirt directs traffic from a long queue.
People at some testing sites waited all day for the swab, while others were turned away.(ABC News: Chris Le Page)

Source of outbreak still unknown

Health authorities are still working to identify the “index case” in the restaurant cluster, which is also known as the Mentone-Mitcham cluster.

He said one diner at the Smile Buffalo restaurant had been in New South Wales prior to testing positive, but their exact movements “don’t quite line up completely”.

But he said the fact all the cases detected in the past few days were linked was encouraging.

“It’s still relatively early days and if further cases pop up then there could still be cause for concern and that’s why we’re wearing masks and there are limits to private household gatherings,” he said.

There were no new cases acquired interstate or detected in returned travellers in hotel quarantine.

There were 32 active cases in Victoria on Sunday, including people in mandatory hotel quarantine.

A busy street in Melbourne.
Victoria had recorded more than six weeks without a local case before the restaurant cluster emerged.(ABC News: Patrick Rocca, file photo)

In response to the growing outbreak in NSW, Victoria has introduced a hard border to its northern neighbour.

About 60,000 people returned over New Year’s Eve and New Year’s Day, before people were turned around at the border.

Hundreds more remain stuck on the NSW side, including about 1,500 who have applied for exemptions to cross the border.

All 60,000 returned travellers should have received a text message advising them of their obligations now they have returned.