Opposition lawmakers will send a joint letter to Prime Minister Hun Sen’s government early next week requesting proof that the map used to define the Vietnamese border matches the constitutionally mandated map held by the United Nations.

Lawmaker Um Sam An of the opposition Cambodia National Rescue Party claims that Va Kimhong, a senior minister in charge of border affairs, is using a map drawn by the Vietnamese and used for border treaties inked in 1985 and 2005, rather than the parameters set forth by the UN map and former King Norodom Sihanouk in the 1960s.

An said yesterday that more than 10 CNRP lawmakers will sign the request.

“He has used the wrong map,” he said. “We want to be 100 per cent clear.”

An added he had a document signed by Kimhong and the president of the Vietnamese border committee from 2007 requesting an improperly scaled map.

Va Kimhong declined to comment yesterday but said in a forum last week, in response to the CNRP lawmakers’ allegations, that he would provide the map.

“If [Um Sam An] does not understand the map, or does not have the official map, please come get the map from us," Kimhong said at the time.

“Our border committee is not too stingy to explain it to him, but please stop propagandising nonsense that creates misunderstandings,” he added.