BANGKOK, Sept 3, 2025 (BSS/AFP) - Thailand's acting prime minister has moved to dissolve parliament, his party said Wednesday, after the largest opposition party backed a rival candidate to lead the country.

Prime minister Paetongtarn Shinawatra was ousted by the Constitutional Court last week over her handling of a border row with Cambodia, leaving a power vacuum in the kingdom's top office as rival factions jostled to replace her.

Her Pheu Thai party -- still governing in a caretaker capacity -- had courted the power-broking opposition People's Party to back its own new candidate for prime minister.

But the People's Party declared its support for conservative tycoon Anutin Charnvirakul instead.

Just moments later, Pheu Thai secretary general Sorawong Thienthong told AFP that acting Prime Minister Phumtham Wechayachai "has submitted a house dissolution decree".

According to the Thai constitution, if the king approves the dissolution of parliament, an election must take place between 45 and 60 days later.

- Covid and cannabis -

Pheu Thai are the current electoral vehicle of the Shinawatra dynasty, which has for two decades jousted with the kingdom's pro-monarchy, pro-military elite.

But their influence is in decline, analysts say, and they are struggling to keep a grip on power.

The People's Party pledged its 143-strong parliamentary bloc to back Anutin, heir to a construction engineering fortune who previously served as deputy prime minister, interior minister and health minister -- in 2022 delivering on a promise to legalise cannabis.

Charged with the tourist-dependent kingdom's Covid-19 response, he accused Westerners of spreading the virus and was forced to apologise after a backlash.

But with parliamentary dissolution pending, it is unclear whether he will make it to the top office.

Anutin's Bhumjaithai Party was a key coalition backer of former prime minister Paetongtarn but abandoned their pact to govern this summer over her conduct during a border row with Cambodia.

That same dispute saw Paetongtarn sacked by the Constitutional Court on Friday, after it found she had breached ministerial ethics in the spat.

Only candidates nominated as potential premiers in the 2023 election are eligible to serve as prime minister, and a streak of turmoil had seen the number of potential leaders whittled down to just five.

The People's Party had said its backing of Anutin was also conditional on house dissolution and fresh polls within four months -- meaning his elevation to office would also set the stage for an election.