Two former Bank of China managers and their wives were handed lengthy jail terms on Wednesday for their roles in a $US485 million ($A649 million) fraud, US justice authorities said.

The two men, Xu Chaofan and Xu Guojun, were convicted by a federal jury in Las Vegas last August of masterminding an elaborate plot that saw them attempt to embezzle hundreds of millions of dollars.

Xu Chaofan was sentenced to 25 years in prison while Xu Guojun was handed a 22-year jail term. Both wives of the men received eight years in prison each and all four were ordered to pay $US482 million ($A645 million) in restitution.

A third bank manager, Yu Zhendong, had pleaded guilty and cooperated with US government prosecutors trying the case.

During last year's trial, jurors heard how the managers laundered stolen millions through a network of accounts in Hong Kong, Canada and the United States, where they had planned to immigrate.

All five defendants were charged with a criminal conspiracy that began in 1991 and continued until October 2004 when the former bank managers and their wives were arrested.

The court heard how the former bank managers created a series of shell corporations in Hong Kong which were used to funnel the cash into personal bank and investment accounts.

Some of the money ended up on gaming tables at Las Vegas casinos, where the accused would frequently lay lavish bets of up to $US80,000 ($A107,000) dollars.