Police investigating failed car bombings at Glasgow airport and London have seized a man at Brisbane airport.
The Australian arrest brings the number of people held to eight.
Australian PM John Howard said the 27-year-old man was a doctor and that a second doctor was also being interviewed by Australian police.
Meanwhile, three controlled explosions have taken place on a car linked to the Glasgow airport attack, outside a mosque in the south of the city.
Supt Stuart Daniel, of Strathclyde Police, said that while there had been "absolutely no specific information" that the car was a threat, the explosions were carried out as a precaution.
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Mr Howard said Australian police had been acting on information from the UK authorities.
The detained man was an Indian national who was arrested while trying to return to India with a one-way ticket, he added.
Attorney General Philip Ruddock said police had executed search warrants at the Gold Coast Hospital in Southport, eastern Queensland - where the man worked as a registrar - as well as at a number of locations across the state.
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Queensland Premier Peter Beattie said the man had been working at the hospital since September and had been based in Liverpool when he answered an advert in the British Medical Journal in March 2006.
Staff at the hospital regarded the man as "a model citizen with excellent references," h
