The Pheu Thai Party is likely to formally reject Democrat leader Abhisit Vejjajiva's reform plan today.
The move is anticipated after key government figures slammed Mr Abhisit's proposal, which requires caretaker Prime Minister Yingluck Shinawatra to step down as part of the reform process.
Caretaker Labour Minister Chalerm Yubamrung, director of the Centre for the Administration of Peace and Order (Capo), said Pheu Thai and the prime minister will not go along with the proposals because the plan is unconstitutional.
He echoed Pheu Thai's strategist Noppadon Pattama's opinion that Mr Abhisit’s plan has huge flaws, including a call for the Senate speaker to appoint a neutral and interim prime minister.
Mr Chalerm insisted the Senate speaker is not authorised to act in such a way and the constitution requires the prime minister, who must be an elected MP, to be nominated by the House of Representatives.
"He is calling for a neutral interim prime minister. Who would this person be? What is he [Abhisit] thinking?'' Mr Chalerm said.
The Capo director said Mr Abhisit's plan cannot be implemented without a coup. However, he expressed confidence that a military putsch is not on the cards.
Mr Chalerm said Capo will issue a statement today urging the Constitutional Court to exercise prudence when it rules on the status of Ms Yingluck in the Thawil Pliensri transfer case.
The statement coincides with today's court hearing on the case.
The court has summoned Ms Yingluck, former national police chief Gen Wichean Potephosree, reinstated National Security Council secretary-general Thawil Pliensri and senator Paiboon Nititawan to testify today.
While the court is unlikely to make a ruling today, Mr Chalerm said he believes it will not be in favour of the caretaker prime minister and will create a political vacuum which may lead to confrontations.
If the court oversteps its authority with the ruling, red shirts and other "politically neutral" groups will not accept it.
According to Mr Chalerm, if the court rules to disqualify the cabinet that ordered Mr Thawil's removal, untoward incidents could result.
Some current cabinet ministers who did not take part in that decision can carry on in their caretaker roles, and the caretaker government will be able to seek a royal decree calling for fresh elections, tentatively scheduled for July 20.
Mr Chalerm also said a Pheu Thai-led government would take office for six months to carry out political reforms, then dissolve the House of Representatives and call new elections.
The Capo director poured scorn on Mr Abhisit's offer to take a break from politics if his reform proposal is accepted, saying the Democrat leader is aware his party will never win a mandate to form a government.
Mr Abhisit defended his plan, saying it does not breach the charter and it is not a "silent coup", as suggested by some Pheu Thai members.
He said he welcomed any criticism, but stressed that the final decision lies with Ms Yingluck.
If she issues a royal decree setting the election date within this week, it means she has rejected the proposal.
He warned Ms Yingluck will find herself in a predicament if the court rules to strip her of her caretaker role.
The court ruling is likely to spur a series of situations that may lead to conflicts.
He said his plan does not go against democratic principles because it demands nothing but willingness and consent to lift the country out of political crisis.
As for a call for the Senate speaker to appoint a neutral interim prime minister, he said the Senate speaker will have to work out an appropriate procedure.
His proposal calls for a neutral prime minister who is free from political influence and affiliation, and is acceptable by rival parties.
He said the proposed referendum will decide on the make-up of the reform council, and possibly the issues requiring reform.
Mr Abhisit floated his reform plan last Saturday, describing steps to take within a time frame in an attempt to put a stop to the crisis.
Party spokesman Chavanond Intarakomalyasut said the party never heard a word from Ms Yingluck after the reforms were unveiled.
He said if the cabinet issues a royal decree for the election date, Ms Yingluck ''slams the door'' on herself and the people.