Thailand’s main opposition parties easily bested other contenders with virtually all the votes counted from Sunday’s general election, fulfilling many voters’ hopes that the balloting would serve as a pivotal chance for change nine years after incumbent Prime Minister Prayuth Chan-ocha first came to power in a 2014 coup.

With 99 per cent of the votes counted by early Monday morning, the junior opposition Move Forward Party had eked out a small edge over the favoured Pheu Thai Party, whose leaders earlier in the night conceded they might not finish on top.

The winner of Sunday’s vote is not assured the right to form the new Government. A joint session of the 500-seat House of Representatives will be held with the 250-member Senate in July to select the new Prime Minister, a process widely seen as undemocratic because the Senators were appointed by the military rather than elected but vote along with Sunday’s winning lawmakers.

Sunday’s voter turnout was about 39.5 million, or 75 per cent of registered voters.

The maverick Move Forward Party captured just over 24 per cent of the popular vote for the House of Representatives’ 400 constituency seats and an almost 36 per cent share of the vote for seats allocated in a separate nationwide ballot for the 100 members elected by proportional representation.

Pheu Thai Party lagged slightly behind with just over 23 per cent for the constituency seats and about a 27 per cent share for the party list.

The tally of constituency votes gave Move Forward 113 House seats and Pheu Thai 112, according to the Election Commission, which did not give a projection for party list seats.

Prayuth’s United Thai Nation Party held the fifth spot in the constituency vote with almost 9 per cent of the total, but it placed third in the party-preference tally with close to 12 per cent. Its constituency vote gave it 23 House seats.

Paetongtarn Shinawatra of Pheu Thai Party, one of the candidates for Prime Minister. Photo / AP

The three parties were considered before the vote to be the most likely to head a new Government. Paetongtarn Shinawatra, 36-year-old daughter of former billionaire populist Prime Minister Thaksin Shinawatra, had been favoured in opinion polls to be chosen the country’s next leader.

Move Forward’s leader, 42-year-old businessman Pita Limjaroenrat, now seems as likely a prospect.

Prayuth had been blamed for a stuttering economy, shortcomings in addressing the Covid pandemic and thwarting democratic reforms, a particular sore point with younger voters.

The returns were a good sign for democratisation, said Saowanee T. Alexander, a professor at Ubon Ratchathani University in northeastern Thailand.

“This is people saying that we want change ... They are saying that they could no longer take it. The people are very frustrated. They want change, and they could achieve it,” she said.

Thailand's Prime Minister, Prayuth Chan-ocha. Photo / AP

Move Forward outperformed even optimistic projections, and the party appeared poised to capture all, or almost all, 33 House seats in the capital, Bangkok.

Along with Pheu Thai, it campaigned for reform of the military and the monarchy. But Move Forward put those issues closer to the heart of its platform, earning a more radical reputation.

Its outspoken support for minor reforms of the monarchy, while winning younger voters, antagonised conservatives to whom the royal institution is sacrosanct.

Pheu Thai is the latest in a string of parties linked to Thaksin, who was ousted as Prime Minister by an army coup in 2006. The Government of his daughter Paetongtarn’s aunt, Yingluck Shinawatra, who became Prime Minister in 2011, was toppled in the coup led by Prayuth.

Paetongtarn Shinawatra (left) is a candidate for Prime Minister from Pheu Thai Party. Photo / AP

Pheu Thai won the most seats in the last election in 2019, but its arch-rival, the military-backed Palang Pracharath Party, succeeded in cobbling together a coalition with Prayuth as Prime Minister. It relied on unanimous support from the Senate, whose members were appointed by the military Government after Prayuth’s coup and share its conservative outlook.

Ubon University’s Alexander cautioned that the current situation remains “very unpredictable,” and that the Election Commission could unilaterally affect the results. In the past, it has used its authority to disqualify opposition parties or otherwise cripple challenges to the conservative establishment.

Move Forward’s Pita would be a possible target for what the opposition, from bitter experience, calls dirty tricks. A candidate from the military-backed Palang Pracharath Party last week filed a complaint with the Election Commission and the National Anti-Corruption Commission, charging that Pita had failed to list a stock shareholding on a statutory declaration of his assets. Pita denied any wrongdoing, and the accusation hinges on a minor technical point.

However, the leader of the Future Forward Party, the forerunner of Move Forward, lost his seat in Parliament on similar technical grounds, and his party ended up being dissolved. It had also been seen as a radical challenge to the military-backed royalist establishment.