SA Health says a Victorian truck driver has tested positive for COVID-19 at the border testing site at Yamba, in the Riverland.
It said the man in his 20s continued driving through South Australia towards Western Australia before being notified of the result.
He was then escorted to an Adelaide medi-hotel.
Service stations in Port Augusta and Yamba were named as exposure sites on Saturday night.
More than half a dozen positive truck drivers moving through the state in recent weeks.
The man had a coronavirus test on Friday and the result came back on Saturday.
Another driver tested positive after a test at Yamba on Thursday night.
Yamba is on the Sturt Highway, the main route between Adelaide and Sydney.
From Thursday, all truck drivers entering South Australia from NSW, the ACT or Victoria must have had at least one COVID-19 vaccination.
Airline crew member positive
Earlier on Saturday, it was announced that a Virgin Australia cabin crew member had tested positive for COVID-19, with six flights between Melbourne and Adelaide, Sydney and Newcastle now listed as exposure sites.
Those flights include VA219 From Melbourne to Adelaide and VA218 Adelaide to Melbourne on October 4, VA827 Melbourne to Sydney and VA808 Sydney to Melbourne on October 5 and VA1593 Melbourne to Newcastle and VA1594 Newcastle to Melbourne on October 6.
The 25 passengers on the flight into Adelaide have been contacted by SA Health.
They were already doing 14 days' quarantine as required when entering South Australia from Victoria.
The airline's staff have also been identified as primary close contacts.
