BANGKOK (Reuters) - Thailand’s election panel asked a court on Thursday to decide if a contested formula used to calculate the 150 “party seats” for the House of Representative was valid and lawful, almost three weeks after a poll whose results it plans to announce on May 9.

FILE PHOTO: Ballots are counted during the general election in Bangkok, Thailand, March 24, 2019. REUTERS/Athit Perawongmetha/File Photo

The March 24 vote was conducted under a complicated electoral system that critics say was devised by the military government to weaken democracy, but which the ruling junta says will ensure stability.

The move raises the prospect of further delay after a lack of clarity over the election outcome fueled concerns over alleged manipulation by the military government, while “democratic front” anti-junta parties say they have come under more scrutiny by the authorities since the vote.

The Election Commission asked the Constitutional Court to rule on “the calculation that may make some parties with votes lower than the average vote won gain one party seat,” and whether such allocations are lawful, it said in a statement.

The court has yet to set a date to hear the case, said a court official who asked for anonymity.

A political deadlock looms as the Pheu Thai Party, formed of the loyalists of ousted former premier Thaksin Shinawatra, has joined an opposition “democratic front” alliance trying to block junta leader Prime Minister Prayuth Chan-ocha from staying in power and official results could be delayed.

Preliminary election results show Pheu Thai, the leading anti-junta party, has won the most constituency seats, while the pro-army Palang Pracharat gained the most votes but each is unable to form a government on its own.

Parties in the election are contesting the way in which the 150 “party seats” are calculated, as these are allocated on the basis of the votes each party gained nationwide, in a system that “caps” the total number a single party can gain.

With a voter turnout of 74.69 percent in the election, the threshold for one “party seat” is just a little over 71,000 votes, according to a formula in the constitution drafted by a junta-appointed panel.

The election panel wants to round up decimals in allocating seats, a procedure that would give seats to 11 small parties whose popular vote fell short of the threshold required, but which large political parties say breaches the constitution.

“For a political party to receive a party seat, that party must gain votes no lower than the allocated value for one seat...based on the law, there is no other way a party can gain a seat,” Pheu Thai said in a statement on Wednesday.

“It is a good thing the election commission has asked the constitutional court to decide on this so it will be conclusive after many questions were raised,” Thanakorn Wangboonkongchana, a deputy spokesman of Palang Pracharat, told Reuters.