It comes as the total number of coronavirus cases recorded in South Australia since the pandemic began today climbed to 583, with four new cases detected in the past 24 hours.

All four cases are people who have recently returned from overseas and have been quarantining in a medi-hotel.

They include three women in their 20s and one man in his 30s, who returned positive test results on day one of quarantine, bringing the total number of active cases in the state to 13.

Victoria’s three confirmed infections bring the total number of active cases in that state to 36.

It is unknown if all the new local transmission infections are linked to the Black Rock cluster in bayside Melbourne, which totalled 21 people on Sunday.

SA Health has advised South Australians travelling in or out of Victoria to monitor the Victorian Health website for updates and get tested immediately if they develop coronavirus symptoms.

Premier Steven Marshall said that the state’s transition committee would meet tomorrow to discuss the situation in Victoria, but for now no changes would be made to the state’s border, which remains open.

It comes after SA imposed a hard border closure with New South Wales on Friday, following the emergence of a concerning cluster of locally-acquired cases in and around Sydney’s northern beaches.

NSW today recorded no new locally acquired coronavirus cases over a designated 24-hour period for the first time in almost three weeks.

In the 24 hours to 8pm Sunday, the state recorded only seven new cases in returned overseas travellers in hotel quarantine.

But two new local cases were recorded after that 24-hour period ended, and will be officially recorded in Tuesday’s figures.

Marshall said the situation in Victoria was different to that in NSW, as all the cases could be linked to previous infections.

“The new cases in Victoria today, I’m informed, are linked to previous infections and so not nearly as worrying as a new infection bubbling up,” he told reporters this morning.

“I have every confidence in the Victorian health team to put that net over that cluster which exists over in Victoria and to bring it under control as quickly as possible.

“But, I do remind people that this is a very fluid situation.”

There were 32,468 tests processed in Victoria on Sunday, up from 22,477, even as some sites were temporarily closed as they battled to cope with a surge in demand driven by returning residents.

More than 60,000 Victorians rushed back from NSW as a hard border between the two states came into effect on Friday night. All were required to be tested once back in Victoria.

It has put testing facilities under strain in recent days, forcing some sites to extend hours and staff to be recalled from holidays.

More than 2500 close primary and secondary contacts of those infected by the Black Rock cluster are quarantining to avoid a major spread.

Victoria’s border is now closed to all travellers from NSW, with some Victorian residents unable to make it home.

Marshall said people in NSW wanting to travel to SA also had an “anxious wait”, after the state imposed hard border restrictions.

He said the border restrictions would not be lifted until NSW recorded 14 days of no locally-acquired coronavirus cases.

“We know that other states are looking for 28 days, but we’ve set ourselves 14 days – that was how we lifted the border with New South Wales before.”

Marshall said health authorities were currently assessing a “huge volume” of applications from people in NSW seeking exemptions to travel into SA.

“We’ve got to make sure we do that evaluation on each of those applications as effectively as we possibly can,” he said.

“We’re always on the look-out where there might be inconsistent information being provided by somebody when they’ve made multiple applications.

“We don’t want to unnecessarily put South Australia at risk, so we are asking people to put those applications in as early as they possibly can.”

The new locally acquired cases reported in NSW today are connected to the Berala BWS bottle shop cluster, which now numbers 15.

One is a man in his 40s who visited the shop on Christmas Eve, and the other a woman in her 40s who has “some association” with the Berala BWS and Woolworths, Chief Health Officer Kerry Chant said.

Genetic sequencing for the Berala cluster revealed the source was a patient transfer worker who took a family of returned overseas travellers to a health facility.

The worker became infected and passed the virus to a colleague, who attended the Berala bottle shop for a “very fleeting amount of time” on December 20.

Anyone who visited the store between December 22 and New Year’s Eve has been ordered to isolate while health officials try to ensure the spread is contained.

Most who dropped by the bottle-shop across the Christmas period are now considered close contacts and need to isolate for 14 days even if they only attended the outlet for a short time.

More than 1000 people who attended on Christmas Eve alone.

The NSW government said testing numbers were still “far too low” and implored residents in western Sydney to attend clinics if they have the slightest of symptoms, even if they have been tested previously.

Some 22,275 people were tested in the 24-hour period ended Sunday night, up slightly from 18,923 the previous day.

The government wants to see about 30,000 or 40,000 tests a day.

Acting Premier John Barilaro said on Monday the government had no qualms about tightening restrictions around Berala if unsourced COVID-19 cases began to emerge.

But he admitted contact tracing at the BWS was a colossal task, as QR codes are not mandatory at NSW bottle shops.

Masks are now mandatory in Sydney shopping centres, on public transport, in places of worship, hair and beauty premises, entertainment venues such as cinemas and other indoor venues like post offices and banks.

Hospitality workers are also required to wear one.

Meanwhile, NSW Police Minister David Elliot has described a breach of public health orders by a venue operator which allowed 700 people to attend a wedding at its southwest Sydney site on Saturday as “baffling”.

Police say the operator will be fined $5000 after officers attended the venue on Spencer St in Fairfield on Saturday. It has a COVID-safe capacity of 350.

“It is a terrible start to the police week … and it is baffling that somebody would breach it so badly,” Elliot said on Monday.

“This isn’t one or two people coming from an area in lockdown or, you know, this isn’t a dozen people that turned up unannounced, this is twice the amount of people that were allowed to attend that wedding reception in an area not far from Berala.”

Guests at the wedding have not yet been fined.

-with AAP and additional reporting by Tom Richardson