They asked the premier to put his signature on a pact of four political parties tomorrow, which will pave the way for amending the constitution.

As part of the political reform and constitution amendment, the coalition plan to ask a "neutral" figure from HM the King to lead the job.

However, Thaksin ruled out the opposition parties' proposal, saying he had earlier assigned rectors of universities nationwide to study about the constitution amendment and he would not surrender to those who did not play by the rule.

Democrat Party leader Abhisit Vejjajiva said the only way-out of the current crisis is to amend the constitution,", adding that the process would pave the way for drafting a new constitution.

He said the amendment would be acceptable if a "neutral" person appointed by His Majesty the King headed the mission.

Abhisit asked other three political parties' leaders - including Thaksin as Thai Rak Thai leader - for a meeting today tomorrow to sign a joint convention to deliver the proposal, which would finally ease the looming political tension.

Mahachon Party leader Sanan Kachornprasart said the opposition parties attempted to force Thaksin back to a process of finding a solution through a parliamentary channel

Abhisit said that the coalition have not yet dropped their wish to boycott the April 2 snap election.

In a dramatic response to the dissolution of the House on Friday, Suriyasai Katasila, the chief coordinator of the People's Alliance for Democracy, called on the three opposition parties, Democrat, Chat Thai and Mahachon, to field no candidates at all and on pro-democracy voters not to choose a constituency or party-list MP.