PHNOM PENH: Fugitive former Thai premier Thaksin Shinawatra arrived in Cambodia to start work as a government economic adviser Tuesday, fuelling tensions after deadly clashes between the two countries.

Thailand has expressed outrage at Cambodia's appointment of Thaksin, who was ousted in a bloodless coup in 2006, and says it will seek the extradition of the billionaire tycoon to serve a two-year jail term for corruption.

The row has plunged relations between the neighbouring countries to their lowest for years, with Thailand and Cambodia recalling their respective ambassadors and Bangkok threatening to close their border.

Thaksin landed in a small private jet at Phnom Penh International Airport and was then escorted into the capital by a convoy of cars under tight security after his early morning arrival, said an AFP photographer at the scene.

"It is an honour for Cambodia's economic sector and we hope that Cambodians nationwide welcome him warmly," Cambodian cabinet spokesman Phay Siphan told a press conference after Thaksin's arrival.

Thaksin is due to address 300 Cambodian economics experts in Phnom Penh on Thursday.

Phay Siphan said Thaksin and Cambodian premier Hun Sen, who are close friends, would likely share a welcoming lunch, and the fugitive leader was expected to stay in the country for "two or three days".

Thaksin, the colourful former owner of Manchester City football club, is living in a variety of foreign locations including Dubai to avoid the jail term imposed by a Thai court in absentia in September 2008.

Thaksin won two elections and remains a massively influential figure in Thai politics after his five years in power, stirring up mass protests by so-called "Red Shirt" supporters against the current government.

His presence on Thailand's doorstep is the closest he has come since he last fled the country in August 2008, a move that is likely to alarm the shaky coalition government of Thai Prime Minister Abhisit Vejjajiva.

Thaksin insisted in an open letter published on his website late Monday that he would "not go to Cambodia to help Cambodia fight with Thailand".

"As I travel to Cambodia to discuss poverty and the world economic situation, I will try to preserve Thai interests with our friends in Phnom Penh, despite the Thai government still hounding me wherever I go," he wrote.

But tensions between Thailand and Cambodia remain high following a series of deadly skirmishes on their disputed border near Cambodia's 11th-century Preah Vihear temple, the last of which was in April.

The temple was granted UNESCO World Heritage status in July 2008, stoking nationalist tensions on both sides.

Thai government spokesman Panitan Wattanayagorn said Bangkok would seek Thaksin's extradition from Cambodia "in one or two days" as soon as the foreign ministry has confirmed Thaksin's address in Phnom Penh.

Thailand's cabinet had also formally agreed to cancel an oil and gas exploration deal with Cambodia that was signed during Thaksin's time in power.

Cambodian foreign ministry spokesman Koy Kuong said his country would not send Thaksin home to face justice in Thailand and was "not concerned about these issues".

"We will not extradite him (Thaksin). We already clarified this case because he is a political victim," Koy Kuong told AFP Tuesday.

Thailand stepped up pressure on Thaksin Monday, accusing him of "violating" the country's revered monarchy after he was quoted in an interview as calling for the reform of royal institutions.

Thailand remains bitterly divided between Thaksin's main support base among the poor, especially in rural areas, and his foes in the Bangkok-based elite power circles of the palace, military and bureaucracy.

Thaksin's visit to Cambodia meanwhile threatens to take the shine off a summit of Southeast Asian leaders with US President Barack Obama that Thailand's Abhisit is due to chair on Sunday in Singapore.