BANGKOK (REUTERS) - Thailand's anti-military Democratic Front alliance will on Wednesday (June 5) nominate rising political star Thanathorn Juangroongruangkit for prime minister, facing off against junta leader Prayut Chan-o-cha, a spokesman said.

The scheduled vote for a new prime minister comes five years after then army chief Prayut seized power from an elected government in 2014.

Thanathorn, leader of the opposition Future Forward Party, entered politics just last year and his party came in third in elections in March.

"The seven democratic parties coalition have jointly decided to nominate Thanathorn for the prime minister's vote tomorrow," Ms Pannika Wanich, spokesman for Future Forward, told Reuters.

Thanathorn faces at least two criminal charges of sedition and cyber crime for allegedly aiding anti-junta protesters shortly after the coup and for a critical speech on Facebook - charges he has characterised as politically motivated.