Taipei - Detained former president Chen Shui-bian Thursday vowed to go on hunger strike - his third since November - to protest against the Taiwan government for holding him and putting him on trial for corruption.

He also said he would terminate the contract with his lawyers to defend for him in the trial, and asked the court to sentence him to life to protest against what he insisted was illegal prosecution and trial.

"I have never been involved in any corruption. Nor have I committed any crimes," he said in a statement issued through his office late Thursday.

His statement came after his request for release from the Taipei Detention Centre was postponed by the court earlier on Thursday.

"It is illegal detention, illegal prosecution and illegal trial," he said, insisting that his suffering was a result of political persecution by China-friendly President Ma Ying-jeou who joined Beijing in suppressing him because of his promotion of Taiwan independence.

Chen has been detained since late December on charges of embezzling 2.97 million US dollars in state funds and accepting 14 million US dollars in bribes as well as money laundering, influence peddling, extortion and document forgery during his two four years in office, which ended in May 2008.

On Tuesday, prosecutors brought fresh graft charges against him for illegally demanding "political contributions."

In the statement, Chen asked Taipei District Court Judge Tsai Shou-hsun to "immediately sentence me to life, and I will not seek appeal and will serve the jail terms immediately."

He also said he would go on hunger strike "immediately" until after May 17 to show support to an upcoming mass protest against Ma.

He was referring to a planned rally by the pro-independence Democratic Progressive Party in front of the Presidential Building on May 17 to protest against the Ma government for its inability to improve the island's dismal economy and siding with China, a rival of Taiwan since the two sides split at the end of a civil war in 1949.

Chen staged his first hunger strike in November for 16 days and another one in February for four days. (dpa)