TAIPEI - TAIWAN'S former president Chen Shui Bian on Friday quit the Democratic Progressive Party (DPP) after money laundering allegations against him and his family surfaced this week.

'I have to say sorry to DPP members and supporters with a heavy heart. I let everybody down and caused irreparable damage to the party. This was not my intention but I made mistakes,' Chen said in a statement.

'To show my deepest remorse, my wife Wu Shu Chen and I leave the DPP from now,' he said.

The statement came hours after Taiwan's premier, Mr Liu Chao shiuan, confirmed that an investigation had been launched into the money laundering claims implicating the Chen family following similar moves by Swiss authorities.

Copies of Swiss documents obtained by Kuomintang lawmaker Hung Hsiu Chu showed that Chen's son Chen Chih Chung and daughter-in-law Huang Jui Ching had transferred some 31 million US dollars (S$43.9 million) to Huang's Swiss bank accounts in 2007.

The former president on Thursday admitted that his wife had wired abroad 20 million US dollars from his past campaign funds, saying she had done so without his knowledge, but he denied money laundering charges.

He also vowed to donate the overseas funds to public affairs.

A string of corruption scandals implicating Chen, his family and top DPP officials has tarnished the party's image and led to its defeat in a March presidential vote.

Chen is already under investigation for allegedly embezzling 14.8 million Taiwan dollars in special expenses from the government while he was president, and his wife is on trial for corruption and document forgery in the same case.

He was named a suspect in the case in 2006 but escaped immediate prosecution because he had presidential immunity. -- AFP