"It is a very sensitive issue that can affect international relations. If the government doesn't allow us to debate the issue first I will file a no-confidence motion," Witthaya Buranasiri, chief opposition whip, said yesterday.
The Cabinet on Tuesday endorsed Prime Minister Abhisit Vejjajiva's decision to rip up the memorandum of understanding signed in 2001 by then-premier Thaksin Shinawatra, under which the two countries stated their intention to jointly develop an overlapping area in the Gulf of Thailand.
Article 190 of the Constitution requires parliamentary approval for any agreements and treaties made with foreign governments.
Witthaya said the government should allow legislators to discuss the revocation without voting on it before having it approved, since it is a big issue with widespread impact.
In the past, Abhisit acted on his own to solve the dispute between Thailand and Cambodia without seeking any opinions from Parliament, including his decision to cancel the MoU, he said.
However, government chief whip Chinnaworn Boonyakiat said the opposition should have picked up a more convenient way of discussion such as proposing an urgent motion in the House meeting, instead of proposing a joint-convention according to Article 179.
Such a convention would require appointment of a special parliamentary meeting.
Reacting to a reporter's question on whether he believed such a meeting would solve the problem, Chinnaworn said the government would be able to solve it.
He said the government was treating the problem with Cambodia according to principles accepted by international norms. It was not provoking conflict.
Thaksin had the right to deliver speeches in Cambodia. However, as a former Thai prime minister, he should not say or do anything that could hurt Thailand, Chinnaworn said.
Pheu Thai MP for Lop Buri, Suchart Lainamngern said he believed his party-mates would not vote to approve this issue. He threatened to sabotage the voting meeting by boycotting it if the issue was brought to the House.
The government was trying to cover its unsolved problems by using Thaksin, he said.
"I think the real cause of the two countries' conflict comes from the conflict of PM Abhisit and Foreign Minister Kasit Piromya with Cambodia. It is not an international conflict, but the government took the issue of former prime minister Thaksin Shinawatra to [create] an international conflict.
"I consider it a political game of the Democrat Party and I will in no way approve of this issue," he said.
Pheu Thai MP for Chachoengsao, Wutthipong Chaisang said he would never vote against the MoU since the government had not provided a real reason why it should be ended.
"If the government tries to cite the issue of Thaksin hurting Thailand and diplomatic relations, I don't think it damaged Thailand in any way," he said.