Thai Prime Minister Prayuth Chan-ocha has "a date in mind" for when parliament will be dissolved, which he said will come before the government's term ends late next month.

He declined to disclose the date in his remarks to reporters late on Thursday, which was the first time Prayuth has said the house would be dissolved early. According to a timeline in the constitution, an election must be held before May 7.

The ballot could make for a grudge match for the premiership that pits two royalist former army chiefs against the billionaire Shinawatra family, whose elected governments the generals helped to overthrow in coups in 2006 and 2014.

Prayuth, 68, has fared poorly in recent opinion polls against the Pheu Thai Party's Paetongtarn Shinawatra, the 36-year-old daughter of Thaksin Shinawatra and niece of Yingluck Shinawatra, both self-exiled former prime ministers.

He is expected to run also against his 77-year-old military mentor Prawit Wongsuwan, his deputy prime minister and veteran political kingmaker from the same royalist army regiment.

Early dissolution could be advantageous to Prayuth, who last month joined the new United Thai Nation party (UTN), as it would allow for more members to be recruited. Under election rules, early dissolution would reduce the minimum period of party membership for election candidates from 90 days to 30 days.

His party has much ground to gain and was sixth in an opinion poll conducted last month with support from just 4.8% of respondents. Pheu Thai was top with 23.4%.

Prayuth took power in a 2014 coup, promising his rule was only temporary. He served as prime minister of a junta and remained premier after a 2019 election. (Reporting by Panu Wongcha-um and Panarat Thepgumpanat; Editing by Martin Petty)