Adelaide's Victoria Park COVID-19 drive-through testing clinic has again been inundated, with people reporting wait times of up to eight hours.
The line of vehicles snakes back more than a kilometre, onto Wakefield and Fullarton Roads.
New exposure sites have also been listed overnight.
Many people have been waiting in line since before midnight, with some taking to social media to vent their frustration.
"It’s 4am and the line for testing at Victoria Park is at the roundabout -so >5 hours wait. This won’t work @SAHealth," one user wrote.
Melbourne woman Kate Schomburgk also took to Twitter at 4am to vent her frustration.
"Waiting in line at Victoria Park for Day 1 arrival testing, 3.5 hours already. Am told still another 5+ hours ahead," she said.
Adelaide expatriate James Endean said the line at Victoria Park was moving "so slowly."
"If I'm guessing at how many cars they're testing, it's probably one every five minutes, so if you've got a set up where hundreds of cars are driving through, that's pretty slow," he said.
"We ended up waiting a little under two hours [to be tested] in Melbourne, and having been tested in Sydney as well, wait times weren't nearly as bad."
SA Health under pressure
Yesterday, South Australia's Chief Public Health Officer Nicola Spurrier downplayed criticisms of SA Health and said more staff had already been recruited to cope with demand.
"There's a shortage of people across the board because our international borders have been shut.
"It's a function of being a small state with a small population."
SA Pathology carried out 20,223 tests across South Australia yesterday, with the daily average testing numbers well above 19,000.
SA Health has taken to its social media channels, asking for patience.
"The significant increase in the number of COVID-19 tests is impacting test result turnaround times," it wrote.
"You should receive your result within 24 hours.
"Please do not call the pathology lab for results earlier than 24 hours after you have had your test."
South Australia recorded 105 new COVID-19 cases yesterday, with two men and three women now in hospital.
None are in intensive care.
New exposure sites have been listed on SA Health's website.
