Aussie granted bail before US extradition

A man facing extradition to the US for his alleged involvement in one of the world's biggest financial swindles has been granted bail in Perth to care for his sick son.

Paul Dion Thompson, 49, has been behind bars since his arrest last week as part of a long-running investigation into global interest rate rigging.

His lawyer Sam Vandongen told the Perth Magistrates Court on Wednesday that Thompson had been aware for 19 months that he could face charges and extradition, but had still travelled to England and Hong Kong to assist authorities.

Mr Vandongen argued Thompson had no criminal record and was not a flight risk because he had family and property ties to Perth.

"To suggest that he would leave in these circumstances ... has no weight whatsoever," Mr Vandongen said.

Magistrate Geoff Lawrence agreed, ruling Thompson could be released on bail with strict conditions pending the outcome of an extradition hearing.

He said Thompson had met the requirements of a "special circumstances" case given one of his son's had a serious health problem and his treatment could be "derailed" by his father's absence.

Thompson must provide a $300,000 recognisance - $100,000 of which must be in cash - and a $500,000 surety before he can be released.

He will also have to surrender his passport, stay away from international departure points and report daily to police.

The court was told Thompson had not yet decided whether to oppose his extradition.

Thompson is among several traders accused of manipulating the London Interbank Offered Rate, one of the world's key benchmark interest rates overseen by the British Bankers Association and representing about 200 banks from more than 60 countries.

He is alleged to have committed the crime while working for Rabobank in Singapore between 2006 and 2011.

Thompson is scheduled to appear in court again on November 25, but no date has been set yet for his extradition hearing.