From Thursday it will be mandatory for South Australians to report their positive rapid antigen test (RAT) results to SA Health.

Premier Steven Marshall announced the change today after initially ruling out mandatory reporting.

"We're keen to track every single one of those results," Mr Marshall said.

READ MORE: Novak Djokovic releases statement to address COVID-19 'misinformation'

"While we think that 95 per cent of people would do the right thing, getting as many positive results into the system just improves that data."

It comes as the state recorded 3715 new COVID-19 cases and seven deaths.

Two free RATs

Close contacts of a positive COVID-19 case that register with SA Health online will be eligible to pick up two free Rats from Thursday.

They will receive a receipt that will need to be presented as proof to receive the free tests.

Only one site will be open tomorrow where people can collect the RATs from in Adelaide's south Parklands, which has a capacity of 13,000.

"We do really want to see what that operation is going to be like through the site in Adelaide," Mr Marshall said.

READ MORE: Almost 60,000 positive rapid tests registered with Service NSW

Cafe fined $10k

Meanwhile, a cafe in Adelaide's outer northern east suburbs was fined $10,000 over allegedly breaching COVID-safe rules.

The owner of the Zitto Café in Golden Groves said a police officer had an issue with the tables being too close together.

READ MORE: Severe thunderstorms sweep through Northern Territory

"I had received no warning to say that I was in breach and I have received no information on how I fix the breach, not knowing specifically what it is," owner Rob said.

"We've been kicked from pillar to post.

"We've done everything to comply for two years so to do this at the back end of two years, it's picking on the low-hanging fruit."

Since going public, Rob's fine has been reviewed and reversed.