South Australia has reported no new COVID-19 infections linked to its local cluster of cases, raising hopes the outbreak has been completely contained.
SA Health says there were no positive swabs among the 13,597 tests conducted on Thursday.
The so-called Modbury cluster stands at 21 confirmed infections with two new cases revealed over the past four days.
Those cases prompted authorities to urge the several thousand people plunged into home quarantine almost two weeks ago to be sure to complete their full 14 days of isolation.
Chief Public Health Officer Nicola Spurrier said people could still become ill.
"Even at this late stage, it is still possible for people to become positive," she said.
"You can be highly infectious, even if you haven't had any symptoms yourself."
The last two positive cases involved a woman in her 80s, who is the wife of a man who also has the virus, and the second was a man in his 40s, whose two adult children previously tested positive.
The Modbury cluster of coronavirus cases began with an 81-year-old man who recently arrived in Australia from Argentina and was quarantined in Sydney before travelling to Adelaide, where he tested positive.
It prompted a week-long statewide lockdown which was lifted on Wednesday.
SA currently has 25 active COVID-19 cases, with the other four found in returned travellers.
All those infected are in hotel quarantine.
Australian Associated Press