Suphap Omsupsin, a leader from PAD's 14 southern provinces, said the group had been monitoring Thai Rak Thai closely and believed it would try to reconvene the House of Representatives without all the seats filled.

The PAD is confident Sunday's polls will fail to produce all 500 MPs because it says many Thai Rak Thai candidates running unopposed will fail to win the required 20 per cent of eligible votes and the party-list has only 99 candidates.

Anti-Thaksin groups have stated that the Constitution requires all 500 MPs to be elected before the first meeting can be convened to select the next prime minister.

But during the past week, several Thai Rak Thai legal experts argued that the Constitution did not clearly state there had to be 500 MPs before the House could reconvene.

Suphap said his group believed Thai Rak Thai bosses knew that not all their 16 one-horse candidates would win the necessary 20 per cent of the vote.

"So it plans to seek loopholes to open the first House meeting," Suphap said.

"But once the House convenes its first meeting, members of PAD across the country will rise up and gather again to protest against the injustice."

He said the uprising would aim to oust the whole Cabinet, not just caretaker Prime Minister Thaksin Shinawatra.

Suphap said southern PAD leaders would hold a meeting this week to map out strategies to stop the House reconvening. Democrat secretary-general Suthep Thaugsuban yesterday said if the Thai Rak Thai forced open the House it would be a dismissal of public feeling.

"There will be a lot of problems if the Thai Rak Thai forces open the House," Suthep said.

"Many people will be angered by the disregard of their feelings."

After the Songkran holiday, Suthep said the people would again start expressing dissatisfaction at the plan to reopen the House.

He said Thai Rak Thai should accept the proposal of Democrat leader Abhisit Vejjajiva, where the caretaker Cabinet resigns and seeks a royally appointed government to carry out political reform.

Suthep said he was not interested in who Thai Rak Thai chose as its next prime minister because none of the candidates would push through real political reform.