BANGKOK Thailand's top court questioned on Tuesday the legality of Bangkok's support for a Cambodian bid to list a disputed Hindu temple as a World Heritage site, giving the opposition another weapon to attack the government.
The Constitutional Court ruled 8-1 that a communique approved by the cabinet in June backing Cambodia's bid to list the 900-year-old Preah Vihear temple had required the approval of parliament.
UNESCO, the U.N. agency for culture and education, voted on Monday to approve Cambodia's request to register the temple, which has been at the centre of a bitter 50-year dispute on the Thai-Cambodian border.
Thailand's opposition Democrat Party jumped on the verdict, saying it would launch a Senate petition to oust Foreign Minister Noppadon Pattama, who sought cabinet approval for the communique.
Under Thailand's constitution, lawmakers can ask the speaker of the Senate to investigate unconstitutional actions by a minister who could be ousted in a vote by the upper chamber.
"We are aiming to terminate Noppadon first," chief opposition whip Satit Wongnongtaey told Reuters. He said they could eventually submit a petition to remove the entire cabinet.
The Democrats and other opponents of ousted Prime Minister Thaksin Shinawatra have whipped up a nationalist frenzy over the temple, which many Thais believe belongs to Thailand, to try to kick out the five-month-old, pro-Thaksin government.
The People's Alliance for Democracy (PAD) -- the motley group of businessmen, academics and royalists whose street campaign against Thaksin led to his removal in a 2006 coup -- said it was mulling its legal options.
"We won't mobilise people to protest against the UNESCO decision, but we will look for ways to oust this government," PAD spokesman Panthep Puapongpan said.
The PAD had accused the government of backing the temple's listing in return for business concessions in Cambodia for Thaksin. The government, Thaksin and Phnom Penh denied the PAD's allegations.
The listing of the temple -- which the International Court of Justice ruled in 1962 belonged to Cambodia, was cheered by Prime Minister Hun Sen and Cambodians on the streets of the capital Phnom Penh.
"This is another proud achievement for our people, the people in the region as well as the whole world that the temple is being recognised as the Khmer's greatest architecture," Hun Sen said in a statement.
UNESCO's Bangkok office said Preah Vihear's listing was based on a new plan which differed from the joint Thai-Cambodian communique issued on June 18 and criticized by the Thai court.
UNESCO said it "has no implications for any ongoing negotiations concerning the boundary between the two countries and does not prejudice the rights of both governments to reach an amicable settlement of the disputed boundary".
Nevertheless, some Thais were angered by the decision.
"The government should have tried much harder in convincing the UNESCO people not to believe what Cambodia has told them. The government must be held responsible," student Natcha Lorsuwannarat said.
Charnvit Kasetsiri, a distinguished Thai historian, said the issue had been politicized by Thaksin's opponents.
"It is not a problem between Thailand and Cambodia, but it is a problem among Thais," he told Reuters Television. "It is a black hole Thais have fallen into and found it hard to get out."
(Additional reporting by Pracha Hariraksapitak and Songphon Koisiriphong in BANGKOK, and Ek Madra in PHNOM PENH)
(Editing by Darren Schuettler and Alex Richardson)