Politicians are unwilling to move from the Pheu Thai Party to the Thai Raksa Chart Party to contest the next election, which is complicating decisions over the allocation of poll candidates for both parties, according to a Pheu Thai source.
Pheu Thai is focusing on winning the constituency race as it has been predicted to capture few, if any, party-list seats under the new election system.
The source said the party was counting on its "sister" party, Thai Raksa Chart, to bring in the party-list seats. If the two win enough MPs, they are likely to band together and form a coalition government along with other aligned parties.
There is also a strong possibility Pheu Thai will not field candidates in all 350 constituencies after several popular politicians defected to other parties.
Pheu Thai has been forced to redesign its line-up and it is expected that even some key party figures might not have a constituency to run in, meaning they might now have to switch to Thai Raksa Chart instead.
Pheu Thai is therefore likely to be short of star politicians during the campaign which could severely affect its vote tally, according to the source.
A number of Pheu Thai politicians who lost in previous elections will fill the Thai Raksa Chart's party-list candidacy slots in order to rake in as many list votes as possible.
However, Pheu Thai has run into problems finding politicians willing to make the switch. Many still feel it will be easier to win votes under the more established, well-known banner.
The source said those defeated in previous polls have asked to stay put and promised to perform better this time around.
This is a setback for Khunying Sudarat Keyurapan, chief of Pheu Thai's strategic committee, as she will now have to work out a new allocation plan after the Election Commission formalises the redesignation of the constituency boundaries, the source added.
Meanwhile, Chaturon Chaisang, a Pheu Thai core member, said he resigned from the party on Friday, though he declined to say if he was defecting to the Thai Raksa Chart.