'The detention clearly violates the presumption of innocence and deprives the freedom of those who are yet to be found guilty,' according to the appeal papers released by Chen's office.

'We request the justices of the constitutional court to order an immediate termination of Chen's detention,' the appeal said, arguing that his legal rights were violated by 'political forces.'

The pro-independence Chen has repeatedly insisted that the charges against him are politically motivated, accusing President Ma Ying-jeou's Beijing-friendly government of leading a witch hunt.

The latest move came after Taiwan's high court last week rejected Chen's appeal against his detention in massive graft cases that have also implicated his family.

The former president was initially locked up for a month after his November arrest on suspected embezzlement and money laundering. He was later released after an appeal from his lawyers and spent two weeks at liberty.

Prosecutors had twice applied for Chen to be put back in custody, succeeding on the second occasion after claiming he could collude with the other suspects and destroy evidence or flee the island if allowed to remain free.

The Taipei district court is set to hold a three-day preliminary hearing on Chen's cases on Monday.

Chen, who left office in May last year after serving a maximum two terms as president, is the island's first former leader to be detained on criminal charges.

Chen, who came to power eight years ago pledging to fight corruption, faces life in prison if convicted on charges of embezzling public funds, taking bribes and money laundering. -- AFP