Phnom Penh - Cambodia has concerns that Thailand's turbulent internal political problems make it unable to effectively work as the new chair of the Association of Southeast Asian Nations, Prime Minister Hun Sen said on Monday.

Hun Sen told reporters after a meeting with US Deputy Secretary of State John Negroponte that ongoing political instability in Thailand was a negative and it should consider volunteering giving up the chair temporarily after taking over in July from Singapore.

"Thailand is in political turmoil but is chairing Asean. I think it would be difficult for Bangkok to hold an Asean summit," Hun Sen told reporters.

"The Thais should hand the chair to either Singapore or Vietnam, but so far these countries are quiet."

Meanwhile, the Associated Press reported from Phnom Penh that Hun Sen was far more insulting to Thailand than first reported. It quoted the Cambodian premier as saying:

"I am wondering whether we can have the summit there since there is no government in Thailand yet. Where else in the world has a government building (Government House) been occupied by protesters like this? Only in Thailand. It is quite weird... [This affects] not just the Thai image exclusively, but Asean's image as well."

The chair of the 10-member group goes in this alphabetical order: Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar (the name used by the regime in Burma), the Philippines, Singapore, Thailand, Vietnam. Thus, Thailand has just assumed the chair from last year's chairman, Singapore, and Vietnam is next in line.

Hun Sen's comments are likely to be taken as a symptom of worsening relations between Cambodia and Thailand over disputed border territory, which has become a powerful domestic political issue on both sides of the border.

The comments are unusual because Asean members normally refrain from commenting on internal issues of other members, but Cambodia claims Thailand again encroached onto its territory over the weekend and troops are now within metres of a third disputed ancient temple.

Hun Sen's cabinet has told local media he is losing patience with what many Cambodians see as violations of their sovereignty but which Thailand says are normal troop movements in disputed areas which have gone without incident for years previously.