Mr Thaksin remains a highly divisive figure in Thailand
Fugitive former Thai Prime Minister Thaksin Shinawatra has flown to the Cambodian capital to take up a job as economic adviser to the government.
He was sentenced in absentia to two years in jail in neighbouring Thailand in a conflict of interest case.
Cambodian Prime Minister Hun Sen offered Mr Thaksin the advisory post on the eve of a regional summit hosted by Thai Prime Minister Abhisit Vejjajiva.
The Thai government has expressed anger and embarrassment about the deal.
Ties between Cambodia and Thailand have been tense in recent months as disputes around a cross-border temple complex have flared.
Campaign base fear
Mr Thaksin landed in a small private aeroplane and was then escorted into the Cambodian capital by a convoy of cars under tight security.
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"Thaksin is now in Cambodia. He flew in on a special flight and just landed at the military airport," said Khieu Kanharith, Cambodian information minister and the top government spokesman.
"We are looking forward to learning from Thaksin's great economic experience and we are convinced that his experience will contribute to our country's economic development," he said.
Mr Thaksin, a former telecoms billionaire, is in self-imposed exile and spends much of his time in Dubai.
He is scheduled to give a lecture on Thursday to 300 economists at the ministry of finance.
Thailand's government is outraged at the Cambodian move, and at Cambodia's apparent rejection of Thailand's judicial imperative to send Mr Thaksin to jail.
The Thai government and its supporters also fear that Mr Thaksin could use his new home just across the border as a campaign base.
Mr Abhisit's government was appointed after defections in parliament followed a period of military rule since the coup in 2006 which deposed Mr Thaksin.
It recalled its ambassador from Cambodia over its appointment of Mr Thaksin after Cambodia would refuse to extradite the tycoon because it considered him a victim of political persecution.
A government spokesman told the BBC that Cambodia valued Mr Thaksin's leadership qualities and business experience and that he would be an asset to the country.
Thaksin ShinawatraFormer Thai Prime Minister Thaksin Shinawatra arrived today in Cambodia where he will take up a post as the government's economic advisor. The appointment has caused a diplomatic incident between the two countries, as Shinawatra was condemned to two years in jail ''in absentia'' for corruption.

Tension is already mounting, with the Thai government expressing both anger and embarrassment over the appointment. They have withdrawn their ambassador and have decided to cancel plans with the Cambodian government for trade and oil exploration. This comes amidst disputes over the Preah Vihear temple complex which spans both countries. Thailand has further threatened to close borders with its neighbour.

Thaksin will address 300 Cambodian economics experts on Thursday in Phnom Penh and is expected to remain "two or three days" according to Cambodian cabinet spokesman Phay Siphan. "It is an honour for Cambodia's economic sector and we hope that Cambodians nationwide welcome him warmly," he announced.

Cambodian information minister Khieu Kanharith also welcomed Thaksin. "We are looking forward to learning from Thaksin's great economic experience and we are convinced that his experience will contribute to our country's economic development," he said.

A coup in 2006 ousted Thaksin after members of parliament defected during military rule. Since then he has been in exile, mostly living in Dubai. He is still influential in Thailand, using protests by the Red Shirts, and the Thai government fears that Thaksin will use Cambodia as base to campaign.

However, Thaksin published a letter on his website on Monday indicating that he did not intend to "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 stated.

Cambodia has made it clear that they will not extradite Thaksin. Cambodian foreign ministry spokesman Koy Kuong said that regarding the jail sentence they are "not concerned about these issues ... We already clarified this case because he is a political victim."