Taiwan's high court has reduced the prison sentence for Chen Shui-bian, the former president, from life to 20 years.

Chen and his wife were convicted last year on charges of embezzlement of state funds and money-laundering and the high court upheld the convictions on Friday, but reduced the punishment.

The sentence for Wu Shu-chen, Chen's wife, was reduced to 14 years.

Chen, 59, was found guilty in September 2009 by the Taipei District Court of embezzling $3.15m from a special presidential fund, receiving bribes worth at least $9m, and laundering some of the money through Swiss bank accounts.

He was sentenced to life in prison and fined $6.2m after nearly three years of acrimonious, high-profile court proceedings that involved his wife, son and numerous aides.

Chen's lawyer said his client, who has been held in a suburban Taipei jail for the past 17 months, "was not pleased by the ruling and believes he should have been acquitted".

"But he also believes he has a good chance on the next appeal so he was not particularly upset," Shih Yi-lin said.

Chen is expected to appeal to the supreme court next to overturn the verdict entirely.