Hun Sen, who has appointed Thaksin as his economic adviser, told a news conference at Phnom Penh airport that Thaksin will address a group of 300 Cambodians.

The appointment has further strained Cambodia's relations with Thailand, with the two countries locked in a festering territorial dispute.

Hun Sen arrived back from a trip to Tokyo where he attended an international conference on the development of the Mekong River region hosted by Japanese Prime Minister Yukio Hatoyama.