Thailand's Move Forward Party is seeking to form a coalition government with other opposition parties as unofficial vote counting results showed the opposition winning the majority of seats in the lower house of parliament.

The Move Forward Party, with a strong base among young voters, emerged as the largest party in the House of Representatives with 151 seats, ahead of the other major opposition and pre-election favorite Pheu Thai Party which won 141 seats.

As 99.18 percent vote counting is completed so far, Move Forward Party and the Pheu Thai Party each captured 112 seats out of the 400 constituency seats in the House of Representatives, said Ittiporn Boonpracong, chairman of the Election Commission on Monday.

The Move Forward Party and Pheu Thai Party also secured around two-thirds of the 100 party-list seats decided in a separate poll, which put the two opposition parties well over the 250-seat threshold for a simple majority in the lower house of parliament.

More than 75 percent of the 52 million eligible voters cast their ballots in the election on Sunday, according to the Election Commission.

Under the two-ballot system with one vote for the 400 constituency members of parliament (MPs) and another for their preferred party vying for the 100 party-list MPs, voters elect a total of 500 members to the House of Representatives.

The official election results are pending verification by the Election Commission, which is expected to be due within 60 days, as parties are expected to start negotiations for a coalition government.

Pita Limjaroenrat, the 42-year-old leader of the Move Forward Party, said Monday that he has invited Pheu Thai Party and several other parties previously in the opposition to form the government.

"I have congratulated Pheu Thai leader, Paetongtarn (Shinawatra), for her hard-fought campaign and have invited her to join the coalition. And that includes other five parties in the previous opposition," he told a press conference.

"We have established a contact point, making sure that we have the MoUs in order to form a coalition," he said.

For its part, the Pheu Thai Party said in a statement that it has accepted the invitation but Paetongtarn said the two parties have yet to start negotiations.

The coalition, if materialized, would have more than 300 seats in the lower house of parliament, but would still fall short of the 376 vote simple majority required for its nominee to be appointed the prime minister as 250 senators will join the 500 MPs in the ballot in accordance with the 2017 constitution.

The senators had backed Prayut Chan-o-cha as prime minister after the previous general election in 2019.

Prayut's Ruam Thai Sang Chart Party (United Thai Nation Party) took 23 constituency seats in the election and was ranked third in the party-list poll with some 4.6 million votes bringing another 13 seats.

Prayut told reporters late on Sunday that he respects the election results and will continue to serve the country no matter what his role will be.

Among the parties in Prayut's government, the Bhumjaithai (proud Thais) Party came third among all parties with 71 seats. The Palang Pracharath Party, through which Prayut was elected prime minister in 2019, captured 40 seats. The Democrat Party, the country's oldest existing political party, failed to improve from 2019's score with only 25 seats.

(With input from Xinhua)