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 South-East Asian Nations (ASEAN), Prime Minister Hun Sen said 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.

The chair of the 10-member group, which consists of Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam, goes in alphabetical order.

"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."

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. (dpa)