Queensland has recorded no new locally-acquired cases of COVID-19 two days after a woman from the state’s far north tested positive.

The state government conducted 12,876 tests across Queensland overnight, but there were no positive results for COVID-19 by Wednesday morning.

There had been concerns the relatives and friends of the woman who has COVID-19 – who travelled from the Sunshine Coast to the far north via Brisbane – would test positive.

Chief health officer Jeannette Young is convinced the woman caught the virus at a Melbourne pub and has the more highly infectious Delta strain.

The woman returned to Queensland on July 13 and stayed with friends on the Sunshine Coast. Two days later was told by Victorian officials that she’d been at a tier-one exposure site – the Young & Jackson Hotel in Melbourne.

The woman presented for testing but returned a negative result, and was active in the community on the Sunshine Coast, and to a lesser degree in far north Queensland, while infectious.

She returned a positive result late Monday night, after flying north to Cairns and then travelling by private vehicle to her family’s home at Mareeba.

The woman, aged in her 20s, was fully vaccinated with Pfizer and wore a mask on public transport on the way from the Sunshine Coast to Brisbane airport, and on a Virgin flight VA791 from Brisbane to Cairns on July 16.

Dr Young said test results from the woman’s friends at Maroochydore and family at Mareeba would be a good indicator of whether Queensland was in trouble.

She dined at the Rice Boi restaurant at Mooloolaba on the Sunshine Coast, between 6.45-8pm last Thursday, and shopped at the Sunshine Coast Plaza shopping centre that day, between 3.55-4.15pm.

Meanwhile, South Australia will be declared a hotspot from 1am Thursday, after the southern state began a seven-day lockdown on Tuesday.

Anyone who has been to SA won’t be allowed to enter Queensland unless they are a returning Queensland resident, or have essential purpose exemptions, and any arrivals will have to quarantine for 14 days.

One new overseas acquired case of COVID-19 was detected in hotel quarantine in Queensland on Wednesday.

-AAP