
Meanwhile, a group of senators, academics, national artists and prominent figures handed an open letter yesterday to the Bangkok-based director of Unesco's Asia-Pacific office, seeking a postponement of Prear Vihear's nomination to the UN body.
The letter is undersigned by more than 300 people, including senators Treungjai Buranasompop, MR Priyananthana Rangsit and Rosana Tositrakul, national artist Naooawarat Pongpaibul and former deputy prime minister MR Pridiyathorn Devakula.
The letter requested Unesco delay consideration of Cambodia's nomination because part of its area and related ancient artefacts are situated in Thai territory. Unesco is due to consider the nomination on July 2.
The letter also argued Preah Vihear Temple, built around 1,100 years ago, is an important trans-boundary heritage whose integrated complex and related parts are situated in both Thai and Cambodian territories, even though the International Court of Justice ruled the temple belonged to Cambodia.
As a result, both countries should jointly nominate Preah Vihear as a World Heritage site.
Senator Truengjai said many Thais were worried that Foreign Minsiter Noppadon Pattama had dubious intent in signing the joint communique with Cambodia.
Senator Rossana said the government's endorsement of the Cambodian bid was related to Thailand's national territory, so the government was required by the Constitution to seek approval from Parliament.
"The government endorsed Cambodia's nomination without transparency," she said. "We don't know why it agreed to a border map of the ancient temple in a hurry. We're gathering signatures from at least 63 MPs and senators in order to file a complaint against the government before the Constitution Court."
Senator MR Priyananthana said Cambodia's nomination was incomplete because some components of the temple, such as a giant pond and Naga staircase, are in Thai territory.
She said Thailand could lose the right to manage the site and its parts in Thai territory if Cambodia's nomination won Unesco approval.