President Arroyo has faced weeks of mounting criticism

They are expected to choose the weakest option, and are then highly likely to vote it down, effectively thwarting any attempt to oust her from office.

Mrs Arroyo faces accusations of corruption and electoral fraud.

She denies any wrongdoing but admits to a "lapse in judgement" in phoning an election officer during the 2004 poll.

She maintains, however, that she was not trying to influence the results of last year's presidential vote.

Long process

The justice committee is expected to choose to take up what is seen as the weakest allegation against Mrs Arroyo - that she betrayed public trust during last year's election.

ARROYO'S PROBLEMS Accused of using position to influence 2004 poll Husband accused of influence-peddling and taking bribes Son and brother-in-law also implicated Family denies all allegations

The other two complaints include allegations that her family profited from illegal gambling.

Once the committee has decided which option to pursue, it will then decide whether to send the complaint on to the House of Representatives, the lower house.

The motion must be endorsed by at least a third of the House of Representatives before it can be sent to the upper house, the Senate, for a final vote.

Protesters massed on Tuesday to demand Mrs Arroyo's impeachment

A conviction by two-thirds of the Senate would lead to the president's dismissal.

Members of the opposition, however, are already sounding pessimistic of their chances to push any complaint through this far, saying they have failed to muster enough support to pass any impeachment bill in parliament.

"We don't have the numbers," opposition legislator Ronaldo Zamora told the French news agency AFP on Tuesday. "We won't be given a chance to have our evidence presented."

Hundreds of protesters reportedly marched to Congress on Tuesday, urging for Mrs Arroyo to be impeached.

But despite the frequent anti-Arroyo protests in Manila, even the largest such rally has fallen far short of the hundreds of thousands which joined the "people power" uprisings that overthrew President Ferdinand Marcos in 1986 and Joseph Estrada in 2001.