"Cambodia would like to ask for intervention to have an international conference on the issue of the Cambodian-Thai border dispute," Prime Minister Hun Sen said during a ceremony attended by foreign diplomats.
"The issue is very hot. It may cause bloodshed," he added.
He said bilateral efforts to resolve the conflict with Thailand would not work and called on the United Nations, the Association of Southeast Asian Nations and other countries to help resolve the spat.
Tensions between the two nations over the disputed border have flared up following protests in Bangkok by the royalist "Yellow Shirt" movement over the issue.
Thai media quoted Prime Minister Abhisit Vejjajiva as saying over the weekend that he was ready to use both diplomatic and military means to settle the dispute.
Thailand's opposition has accused the government of using the spat to fuel patriotism and boost its domestic political support.
Hun Sen wrote to the United Nations on Sunday accusing Thailand of violating UN rules by threatening to use military force against Cambodia.
Cambodia reserves its "legitimate rights to defend its sovereignty and territorial integrity in case of deliberate acts of aggression," Hun Sen wrote in the letter, which was distributed to the media.
Abhisit said Monday that the letter was based on incorrect information.
"Cambodia wants to give an image of Thailand as an intruder or using force, which is not true," he told reporters.
"We are Thais, whatever the problem we should talk."
Cambodia and Thailand have been locked in a troop standoff at their disputed border since July 2008, when the ancient Preah Vihear temple was granted UNESCO World Heritage status.
Troops from both countries exchanged fire briefly on their border in June, the latest in a series of clashes between the neighbours.