People in Thailand have just marked the traditional New Year holiday period with the Songkran Festival. The mood was upbeat as revelers took to the streets for the customary water fights. But candidates in the upcoming election weren't taking any time off to relax.

Thai Prime Minister Prayut Chan-o-cha surprised crowds at the Bangkok festival site with an unannounced visit. Prayut seized power in a 2014 coup. He subsequently had another period in office and is now vying to be returned.

But the latest polling shows he has his work cut out. Prayut is trailing as preferred prime minister, with less than 14 percent of support. His United Thai Nation Party is faring even worse in the preferred party stakes, with just 11 percent.

The biggest opposition group, the Pheu Thai Party, commands 47 percent of the support.

The party's candidate Paetongtarn Shinawatra is also leading the race for preferred prime minister, with around 36 percent. Paetongtarn is the daughter of fugitive former Prime Minister Thaksin Shinawatra and the niece of Yingluck, the leader ousted in the 2014 coup.

Pita Limcharoenrat leads another opposition group, the Move Forward Party. He is in second place as preferred prime minister, and closing the gap. He now has 20 percent of support, 5 points up from a month ago.

His party is targeting younger voters by pledging to end military conscription, among other policies. The party is in second position with 21 percent of support.