Bangkok: Coup leader General Prayuth Chan-ocha on Tuesday took office as the Prime Minister of Thailand in a ceremony at the government headquarters, opening a new phase in the country after five years of a military junta.

Prayuth was elected Prime Minister in a vote in Parliament on June 5, but his appointment became official on Tuesday after King Maha Vajiralongkorn's approval was published in the Royal Gazette, the country's official bulletin.

During the swearing-in, 65-year-old Prayuth, dressed in a formal white uniform, knelt before a portrait of King Maha Vajiralongkorn, who was not present, Efe news reported.

"I affirm that I will dedicate myself to public service with honesty and integrity in pursuit of the greater good of the country and the people of Thailand," the Prime Minister said at a press conference after the event, in which he expressed gratitude to the monarch and promised to fight against corruption and inequality.

"I will listen to the voices of the people while fulfilling my duty to move forward and develop the country in all economic and social aspects," Prayuth added.

Prayuth was the Army chief when he seized power in a coup in May 2014 after months of anti-government protests that had hampered the holding of elections that year.

A man with an abrasive manner and an ultra-monarchist, he has silenced any form of dissent and pushed back the holding of elections several times.

The general did not contest the elections, held on March 24, but was named the prime-ministerial candidate by the pro-junta Palang Pracharat party, which won the popular vote but not the most seats.

Prayuth was earlier appointed the head of government with 500 votes from a large coalition of parties and all the senators - handpicked by the military junta - in a special joint session of the Senate and lower house.

The incumbent prevailed by 500-244 over Thanathorn Juangroongruankrit, a political newcomer, who was backed by a coalition of anti-junta parties.