Thailand's populist Pheu Thai party has announced it will form a coalition with a party from the outgoing military-backed administration to try to end nearly three months of political deadlock after the progressive party that won national elections was excluded from the formation of a new government.

The progressive political party that won the most seats in Thailand’s general election has been excluded from a coalition to form the next government.

Thailand’s Election Commission says there is evidence that the top candidate to become the country’s next prime minister, a reformist with strong backing among progressive young voters, violated election law.

Thailand’s new Parliament has convened nearly two months after a progressive opposition party won a stunning election victory, but there is still no clear sign that its leader will be able to become prime minister and end nine years of military-dominated rule.

Thailand’s main opposition parties have easily bested other contenders with virtually all the votes counted from Sunday’s general election.