Meanwhile, the ACT has recorded one new case in a returned traveller and Victoria has surpassed the benchmark for eliminating coronavirus, recording a 29th straight day without a single new infection.
The two South Australian cases are a child from the original family at the centre of the Parafield cluster and a man in his 30s believed to have contracted the virus while attending an English language school next to Flinders University.
The child was already in quarantine and poses no risk to the public, the state’s chief public health officer, Nicola Spurrier, said.
The other case and his family were also in quarantine before they tested positive.
Spurrier said the man’s infection validated the decision to ask some casual contacts to self-isolate.
“This person was considered a casual contact rather than a close contact and again it absolutely backs up the information we were already giving to people,” she said. “We’re seeing people that have got infected through fairly brief contacts.”
The diagnoses bring the Parafield cluster to 33 people.
ACT health authorities say a woman in her 20s who returned to Australia on a government-facilitated charter flight that arrived on 26 November contracted the virus more than a month ago while overseas.
“She returned a low positive result during routine testing on day one of mandatory quarantine. We believe this represents her old overseas-acquired infection,” the ACT government said. “She is not considered infectious and contract tracing will not be required.”
Despite the eight new cases in quarantine, NSW has reached three weeks without any new locally transmitted coronavirus cases. More than 12,000 tests were conducted in the 24 hours to 8pm on Friday.
In Victoria, zero positive results were returned from more than 9,000 tests in the previous 24 hours.
At the peak of the second wave, on 11 August, Victoria had 7,880 active cases.
The last Covid-19 patient in a Victorian hospital was discharged on Monday, leaving the state without an active case, and Friday marked four weeks since the last new case was diagnosed.
Health authorities say 28 days with no new infections means the virus has been eliminated from the community, given that period represents two 14-day incubation periods.
Victoria’s milestone means other states will begin welcoming travellers from the state once more. NSW lifted restrictions for Victorian travellers on Monday, while Queensland and South Australia will reopen their borders from 1 December.
Western Australia is now the only state or territory with closed borders to Victoria and no plan to reopen them.
As South Australian health officials continue to grapple with the coronavirus outbreak, the state’s business sector is calling for compensation amid ongoing restrictions in the lead-up to Christmas.
The state government will implement a two-week, step-down strategy in easing measures imposed at the start of the outbreak.
That will include opening the borders to Victorians from 1 December and scrapping limits on the number of patrons in pubs, restaurants and cafes.
But a general work from home advisory remains in place along with a one person to every four square metres rule for all indoor venues.
Business SA chief executive Martin Haese said that meant most businesses would be operating at 25% capacity, which was not financially viable.
He said the continued measures would have a significant impact on the hospitality, retail, events and leisure sectors at what is their busiest time of the year.
“Business SA also has grave concerns for the city with work from home advice all but cancelling Christmas for city traders, who will wear the brunt of this as they have all year,” Haese said.
He has called for the government to relax the eligibility criteria for the $10,000 emergency grants to help businesses get through the Christmas period.
Meanwhile, Scott Morrison told the Liberal party’s NSW state council that Australia’s debt situation was the envy of the world.
“Net debt as a share of the economy will peak at half of what it is in the United Kingdom, a third of what it is in the US and a quarter of what it is in Japan,” the prime minister said.
Morrison said taking on huge debt as Liberals who were traditionally economically conservative was about “understanding the necessity of action”. “None of us likes the fact that we have had to take on now such a heavy load. But it is necessarily so and I think Australians have heavily supported us in that.”
The prime minister, speaking from isolation at the Lodge because of his recent trip to Japan, said the more than 55,000 Covid deaths in the UK was more than during the blitz in the second world war.
“Our relative success here in Australia sometimes shields us from the sheer scale of the devastation that has occurred elsewhere around the world,” he said.