Mr Thaksin remains a highly divisive figure in Thailand
Former Thai PM Thaksin Shinawatra has accused the country's rulers of "false patriotism" in a speech in Cambodia.
Cambodia has rejected a Thai extradition request for Mr Thaksin.
The Thai government is outraged at Cambodia's welcome to Mr Thaksin, who it sees as a criminal - and a powerful political opponent.
"I see a lot of synergy between your country and mine. What is good for you will also be good for my country. Of course not all my compatriots see it that way right now," Mr Thaksin said in the speech.
"I do not believe those who do not share our vision right now are myopic. Their domestic political compulsions force them to false patriotism," he said, without elaborating.
"Let's pray that they too will one day appreciate this partnership for the best," he added.
Reporters were evicted from the lecture, titled Cambodia and the World after the Financial Crisis.
Mr Thaksin is expected to visit the Angkor Wat temple and to play golf with Cambodian Prime Minister Hun Sen, but is believed to be staying only a few days and not setting up residence in Cambodia.
"I'll try my best to explain my experiences and share the knowledge that I gathered during my exile," he said.
Mr Hun Sen has dismissed Thai government demands that Mr Thaksin be surrendered to serve a two-year jail term for corruption, citing his friendship with Mr Thaksin.
former Thai Prime Minister Thaksin Shinawatra (R) shaking hands with Cambodian Prime Minister Hun Sen (L)
Mr Thaksin (r) and Cambodian PM Hun Sen play golf together
Thailand has frozen an Memorandum of Understanding regarding joint exploration of shared maritime areas, and says it is considering legal options following the extradition rebuff.
Some analysts say the Cambodian leader's belief that the Thai court that convicted Mr Thaksin was politically motivated has particularly angered the Thai government.
Mr Thaksin served as Thailand's prime minister from 2001 to 2006, when he was ousted by a military coup after being accused of corruption and showing disrespect to the country's widely-revered monarch, King Bhumibol Adulyadej.
He has been living in self-imposed exile ever since - mostly in Dubai - but has rarely been out of the headlines, giving a series of high-profile interviews and continuing to make contact with his supporters inside the country.
Relations between Thailand and Cambodia are already strained.
Thailand has withdrawn its ambassador from Cambodia, and there have also been series of disputes centred around the 11th-Century Preah Vihear temple complex near the two countries' border.