SA Health have released a statement confirming that genomics test results returned on Tuesday afternoon now link two people - one of which is today's new case - to the Parafield cluster.
Today's case is a man in his 20s who is a close contact of a previously confirmed case.
He remains in a medi-hotel.
Both these people were previously believed to have overseas-acquired COVID-19.
SA Health say there is "no additional risk to the public" as the cases are linked to a medi-hotel staff member who has previously tested positive for COVID-19 and contact tracing has already been undertaken.
"As a precaution, we are undertaking additional testing at one of our medi-hotels for all staff and guests today," a spokesperson said.
On Monday, the state also recorded one infectious case, a woman linked to the Parafield cluster and has been in quarantine since Monday, November 16.
According to SA Health chief public health officer, Professor Nicola Spurrier, there remains 4100 contacts or contacts of close contacts still in quarantine directly linked to the Parafield cluster.
"..my team is contacting them on a very regular basis, we also have a rolling plan of testing and retesting those people over this period of time," she assured.
Fortunately some of those people in quarantine have almost reached their 14-day isolation timeframe.
"However, before anyone comes out of quarantine they need to have been cleared with a final COVID-19 test," Prof Spurrier said.
She added the turnaround time on testing is swift and people can be notified by SMS.
Meanwhile, on Tuesday, Premier Steven Marshall spoke about normalising the borders as soon as possible.
"We know the Northern Territory has already moved and the ACT and NSW remain open to South Australia," he said.