Health authorities are searching for more than a dozen people who failed to check in at a business visited by an infected Covid-19 case from NSW.

South Australian authorities are scrambling to find more than a dozen people who failed to check in at businesses where Covid-19-positive truck drivers visited.

SA Health was alerted on Friday that two transport workers who travelled from NSW through regional South Australia to get to Western Australia tested positive to the virus.

The truck drivers stopped at locations in Ceduna, Port Augusta and Nundroo along their travels that have now been listed as exposure sites.

As a result, 99 people have so far been directed to isolate for 14 days as a precaution.

But health authorities are still working to determine who a further 18 people are that attended one of the exposure sites and did not use the Covid QR check-in.

Premier Steven Marshall said there were “secondary ways” to identify those missing people but they were ”slower” than the QR system.

He said it was “unlikely” that more people would be directed to quarantine on Monday.

“Again, we’ve been very fortunate in SA (because) we learnt about this infected person being in SA very early,” he said of the first truck driver to test positive.

“We put a net over those people who could have come into contact with this infected person very quickly.

“It’s a bit of a waiting game, but I’m hopeful we won’t have further infections here.”

Essential workers, like truck drivers, must undergo surveillance testing when they cross the border into South Australia, and the Premier said that system identified the initial positive case.

“He was asymptomatic and developed those symptoms early … It shows this system is working well,” Mr Marshall said.

Chief public health officer Nicola Spurrier said SA Health was collating the tests of those 99 people in quarantine and they had so far returned negative tests to Covid-19.

She said the most important thing now was to locate those remaining people so the rest of the community were not at risk.

“We had a bit of an issue because when we looked at the CCTV footage there was not a high compliance rate of QR check-ins at the On The Runs,” Professor Spurrier told 5AA Radio.

“We’re having to go back and look at bank details as well as getting CCTV to see if we can identify people that way.

“It really worrying if somebody’s been exposed, so we want to make sure they know and they’re protected as well as their family and the rest of the community.”

Despite the recent exposure scare, the state recorded zero new Covid-19 infections on Monday.

Anyone who visited the following exposure locations at the specified date and time should get tested immediately and quarantine, along with their household contacts, for 14 days since visiting the location and be tested again on day five and day 13:

  • Ceduna – IOR Petroleum Ceduna at 92 McKenzie St on Saturday, August 21 between 3.45pm to 5.45pm and 10pm to 10.30pm; and Thursday, August 26 between 5.30am and 6.30am
  • Ceduna – OTR Ceduna at 35 Eyre Highway on Saturday, August 21 between 3.45pm and 5.45pm; and Thursday, August 26 between 5.30am and 6.30am
  • Port Augusta – IOR Petroleum Port Augusta (South) at Northern Power Station Rd on Saturday, August 21 between noon and 12.30pm; Sunday, August 22 between 4.05am to 4.35am; Wednesday, August 25 between 11.30pm and midnight; and Thursday, August 26 between midnight and 12.30am
  • Port Augusta – OTR Port Augusta at the corner of Augusta Highway and Northern Power Station Rd on Saturday, August 21 between noon and 12.50pm; Sunday, August 22 between 4.20am to 5.05am; Wednesday, August 25 between 11.30pm and midnight; and Thursday, August 26 between midnight and 12.30am
  • Nundroo – Nundroo Mobile Roadhouse along Eyre Highway on Saturday, August 21 between 7.15pm to 8.30pm

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