TAIPEI, TAIWAN - Taiwanese prosecutors on Friday appealed a ruling against former president Chen Shui-bian and other defendants in a corruption case that could put the ex-leader behind bars for life.

'We file the appeal as some parts of the ruling concerning seven defendants including Chen are improper,' the Supreme Prosecutor's Office said in a statement.

Chen was convicted last week of taking bribes, embezzling state funds and forging documents, among other crimes. His wheelchair-bound wife Wu Shu-chen was also given a life term on graft charges.

However, the prosecutors said Friday they were unhappy with the court's decision not to rule on charges involving Chen and his wife receiving political donations from two businessmen.

They also pointed out that Chen's son was convicted of money laundering rather than a more serious charge of embezzling state funds, and criticised the conviction of the former president's daughter-in-law.

Under Taiwanese law, a life sentence is automatically appealed. But Chen on Monday also filed an appeal against his corruption conviction, Chiang said.

Chen, 58, has blasted the trial as a vendetta carried out by the Beijing-friendly Kuomintang administration over his pro-independence stance during eight years in power.

Taiwan has been governed separately from China since 1949, but Beijing still considers the island as part of its territory and has vowed to take it back, by force if necessary.