The Thai Rak Thai Party appears to be facing a fresh trouble as one of its party-list MP candidates, Premsak Phiayura, recently tendered his resignation and entered the monkhood.

His move has reduced the number of Thai Rak Thai's party-list MP candidates from 100 to 99. Thai Rak Thai had been expected to win all party-list MP seats since all three former opposition parties have boycotted the election and smaller parties will find it tough to garner enough votes to take even one party-list seat.

The law requires there to be the full complement of 500 MPs for the new House to sit and select a premier.

Meanwhile, a Rangsit University poll conducted on March 8-9 shows that the popularity of a "major" political party has plunged from about 10 million supporters to about seven million.

Of the 724 respondents in Bangkok and 1,539 in other provinces, about 32 per cent also said they would tick the "no vote" box in the April 2 election.

The university said the popularity plunge of this "major" party was based on comparison with a poll conducted about a year ago, when the party won 53 per cent of the vote in the last general election.

However, only 22 per cent of respondents said in the latest poll that they would still vote for the No-1 party, which got a total of bout 19 million votes in the last general election.

In response to the latest party-list development, General Akekachai Varunprapa, secretary-general of the Election Commission, said the new House of Representatives following the election had to have 500 MPs - including 100 party-list MPs - before it could convene to select a prime minister.

The small and new parties - most of which are little-known or have never been heard of before - have fielded some candidates, but do not expect to get any MPs from their party lists.

By law, a party-list MP is required to get at least five per cent of the total votes cast in a general election.

Premsak, who has entered the monkhood at Wat Suan Kaew in Nonthaburi, was ranked 93rd on the Thai Rak Thai list.

In his resignation letter, Premsak said the wide rift between Thaksin supporters and the anti-Thaksin group had gone beyond the point of a compromise. He feared the situation was likely to end in violence.

Thaksin wants to go for the election while his antagonists have turned their backs on the campaign, he said.

Premsak said he had decided to enter the monkhood to pave the way for the two camps to sit and talk and reach a way out of the impasse for the benefit of the country.

"Hopefully, my decision will lead to a peaceful solution with no bloodshed among Thais," he wrote. "It will also break the move for the election to be held on April 2."

Observers expect that Thai Rak Thai would stand to win all the 100 party-list seats and most of the 400 constituent seats after three opposition parties - the Democrats, Chat Thai and Mahachon - boycotted the election.

Caretaker Prime Minister Thaksin Shinawatra downplayed concerns that his party would be in trouble after the election because the House session to select the new PM could not be opened.

He said he did not believe Thai Rak Thai would in any case win all the 100 party-list seats, saying some other contending parties could take at least five per cent of the proportional votes.

Premsak's resignation came as the political conflict reached a stalemate with threat of further violence looming after a bomb rocked the home of Privy Council President Prem Tinsulanonda earlier this week.

The three opposition parties have boycotted the general election on the grounds that it is not the right way out and that a fair poll cannot be assured.

Without their participation, the election looked set to produce a one-party House of 500 MPs for Thai Rak Thai as other small parties are expected to fail in their campaigns.