The female tourist arrived in Australia in mid-July and went into mandatory hotel quarantine for two weeks in Sydney, where she returned two negative results.

She was then able to fly from Sydney to Brisbane and go about her normal business.

But when she returned to Japan on August 18, the woman was asymptomatic and returned a positive test result.

It’s prompted Japanese health authorities to contact Queensland Health which issued the warning late yesterday.

Anyone who flew on Virgin Flight VA962 from Brisbane to Sydney on August 17 or dined at the Jam Pantry Cafe in Greenslopes between 9.45am and 11am on August 16 may be affected, the alert says.

Anyone else who dined at the café outside these hours on that day should come forward for testing if they develop any COVID-19 symptoms.

Authorities say the woman was asymptomatic at the time. At least six close contacts have been identified and isolated so far.

Contact tracing is underway in Queensland to identify any other possible links to the woman.

“Because she quarantined in Sydney and travelled straight to Brisbane from hotel quarantine, she could go about her normal life in Brisbane,” Queensland Chief Health Officer Dr Jeannette Young said.

“However, on her arrival to Japan on 18 August, she was asymptomatic but returned a positive COVID-19 result.

“While we are still determining where the virus may have been acquired, we are working with Japanese authorities to gather necessary information.

“We have been in touch with six close contacts in Brisbane identified by the woman. These people have been tested and are now in quarantine.”

Yesterday, Queensland recorded one new case of coronavirus after conducting 11,540 tests in the past 24 hours.

There are six active cases within the state.