Mr Chen has apologised for the scandal but maintains his innocence

The vote is scheduled for 24 November, and if the motion passes it will trigger a national referendum on whether to get rid of the president.

Mr Chen has survived two such votes before, and looks likely to again.

But this time the challenge will be tougher, in the light of prosecutors' claims that they have enough evidence to charge him with corruption.

Mr Chen cannot be prosecuted while in office, as he is protected by presidential immunity, but his wife, Wu Shu-chen, and three ex-aides have already been charged with the misuse of state funds.

Opposition supporters are continuing their demands for Mr Chen to step down over the crisis.

Keeping up the pressure

The opposition parties, which have a small majority in parliament, will need at least 14 ruling party members to back the recall motion in order for it to succeed.

SCANDAL TIMELINE March 2004: President Chen narrowly wins re-election May 2006: President's son-in-law held over insider trading claims Charged in July Allegations of improper conduct involving Chen's wife and senior aides also surface June: Chen cedes some powers to PM amid outcry Unprecedented opposition motion to oust him, which fails September: Two weeks of pro and anti-Chen marches Opposition launch new bid to recall Chen, which again fails October: Wu Shu-chen cleared of accepting shop vouchers in return for influence November: Wu Shu-chen charged with corruption over handling of secret presidential funds Prosecutors say enough evidence to indict Chen, but he is protected by presidential immunity Testing times for Taiwan

The last two attempts - in June and October - failed as all Mr Chen's Democratic Progressive Party (DPP) colleagues stood by him.

Analysts say the big question now is whether the prosecutors' conclusions last Friday will cause some DPP lawmakers to lose faith in their leader and vote in favour of the recall motion.

So far, correspondents say, it appears likely that the vote will again fail. Most DPP members seem to be loyal to their leader, and the party has said it will punish any legislators who vote against Mr Chen.

"The chances of [the bill] passing are low," admitted opposition Nationalist Party legislator Tsai Cheng-yuan, but he added that even if it did not pass, his party would still keep up the pressure against Mr Chen.