Federal Government plays it cool over growing Adelaide cluster

The Federal Government is confident South Australia has a "strong system in place" to contain a spiralling new coronavirus outbreak.

South Australia has reported 17 new cases without a known source of transmission, the first infections outside hotel quarantine since April 16. Yesterday the outbreak totalled just four.

Speaking on Today, Federal Health Minister Greg Hunt said the government had offered to deploy the Australian Defence Force to help South Australia's "excellent" contact tracing operation.

The Federal Government has also instructed the national incident centre contact-tracing to assist South Australia Health.

A woman in her 80s has been identified as the first case in the Adelaide cluster.

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She contracted the virus after she was treated at Lyell McEwin Hospital in Adelaide's north.

Mr Hunt said the virus could be transmitted on cargo from overseas, as well as by the local community.

"Where Australians are coming home, where we're bringing critical medicines in or sending our food to the rest of the world, there's always the risk that somewhere a touch or a surface will see the virus transmitted," he said.

Mr Hunt said states need to be ready for outbreaks until a vaccine is developed, which he has predicted could be by March next year.

He said Australia's contact tracing and quarantine system is one of the "strongest" in the world.