Thailand's biggest opposition party on Thursday said it would seek a court ruling to stop an effort by pro-administration lawmakers to change the electoral system, calling it an unconstitutional move to favour the government.
The Pheu Thai party's challenge comes as Prime Minister Prayuth Chan-ocha, who first came to power in a 2014 coup, nears the end of his term, with an election due by May next year.
Pheu Thai believes a complicated re-jig of the rules sought by pro-government lawmakers is designed to work against big parties and favour the smaller ones with which former army chief Prayuth has built his 17-party coalition.
Legislators late on Wednesday approved at second reading a plan to change the method used to calculate party list seat allocations while rejecting another proposal favored by the opposition bloc.
A third reading and royal approval is still required.
"The vote yesterday shows how General Prayuth wants to remain in power by using the electoral system as his tool," Pheu Thai secretary-general Prasert Chantararuangthong said, confirming a plan to take the issue to the constitutional court.
Government spokesman Thanakorn Wangboonkongchana said the changes sought by lawmakers reflected the majority voice in parliament and had nothing to do with Prayuth or his administration.
Pheu Thai was the ruling party that Prayuth ousted eight years ago in his coup against then Prime Minister Yingluck Shinawatra.
The party is the most recent incarnation of a populist political juggernaut founded by the billionaire Shinawatra family, which has won five general elections, two in landslides in the past 20 years.
The constitution was amended last year to change a voting system that had helped then junta leader Prayuth remain in power after the 2019 election, despite his Palang Pracharat party being beaten by Pheu Thai.
"This will produce similar results to the 2019 election where smaller parties gained seats with few votes," said Stithorn Thananithichot, an analyst at the King Prajadhipok Institute.
(Reporting by Panu Wongcha-um and Panarat Thepgumpanat; Editing by Martin Petty)
