South Australia has reported one new case of COVID-19 linked to a cluster that briefly raised fears of a possible second wave of infections and sparked a short-lived statewide lockdown.

Chief public health officer Nicola Spurrier said the latest case involved a member of the extended family group originally linked to the Parafield cluster.

The case was finally confirmed after an incubation of about eight days and came after the woman had twice tested negative

It takes the total cases linked to the cluster to 27. Just one of those patients, a man in his 30s, is in hospital.

SA now has 38 active cases, including 11 in returned travellers.

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All those with active infections remain in quarantine along with more than 4000 close contacts.

Professor Spurrier said the Parafield cluster was still a risk to the wider community and urged anyone with symptoms to get tested and for the wider community to wear masks whenever possible.

“If we have had more community transmission we will be starting to see it this week,” she said.

Premier Steven Marshall said the state was not “out of the woods yet” but he felt more optimistic that SA had avoided a major second wave of coronavirus infections.

“We stared down a catastrophic situation by acting swiftly and decisively,” he said.

-AAP