BANGKOK (Reuters) - Toppled in a 2006 coup and living overseas to avoid jail for graft, Thailand's former Prime Minister Thaksin Shinawatra has long defied the odds by remaining a political force.

But in the days since his sister Yingluck took power as prime minister he has returned to the headlines with a vengeance, complicating the new government's attempts to win public acceptance and raising the risk of unrest.

Newspapers and television news broadcasts are just as likely to focus on Thaksin, a billionaire former telecommunications tycoon reviled by the country's elite, as his 44-year-old sister, a political novice who says she wants reconciliation in nation deeply divided since her brother's removal from power.

"It seems that he still cannot restrain himself. This is a very dangerous game," said Michael Montesano, a Thai politics expert at Singapore's Institute of Southeast Asian Studies.

From his villa in Dubai, Thaksin is widely understood to have been instrumental in Yingluck's election victory, playing the role of behind-the-scenes powerbroker and adviser despite his conviction by a Thai court of corruption three years ago.

Most had expected Thaksin, who from exile webcam and telephone links to rally thousands of supporters against the previous government of Abhisit Vejjajiva, to lay low and allow his political allies to consolidate power and pave the way for an amnesty that could eventually bring him home.

But he has done exactly the opposite, planning high-profile trips to Japan and Cambodia that have embarrassed Yingluck and detracted attention from her policies.

"This rashness and haste on Thaksin's part have come far sooner than I expected," said Montesano.

"His behavior is causing trouble for Yingluck. I expect that we will see more of this, and that Yingluck's troubles in managing her brother will get worse."

Thaksin's legal advisor Noppadol Pattama told Reuters on Thursday that the former premier had decided to postpone the Cambodia trip, but did not give a reason. The visit, during which Thaksin was expected to meet Prime Minister Hun Sen, was highly contentious because it would have come before any official delegation from the new Thai government.

Thai newspapers reported Thaksin was in Macau on Thursday, where he was scheduled to meet with many lawmakers in Yingluck's party. Noppadol said he could not confirm his schedule.

For Yingluck, the consequences of Thaksin's public attempts to re-assert himself so soon could be devastating.

Since the coup, Thailand has been locked in a polarizing crisis marked by street protests, blockades of airports and government offices, and military and judicial intervention that has either brought down or preserved ruling parties.

The conflict broadly pits Thaksin, his business allies and his mostly working-class "red shirt" supporters against the army's top brass, a conservative elite and a royalist, urban middle-class "yellow shirt" protest movement that despises him.

Despite such powerful opposition, Thaksin's huge popularity in the countryside has ensured parties he has led or backed have won every election in the past decade.

All but Yingluck's Puea Thai Party have been removed from office, through either military or judicial intervention, and analysts say it could suffer the same fate if Thaksin oversteps and tries to run the country from exile.

Yingluck has enjoyed a relatively positive reception since her political career began just three months ago. According to an opinion poll this week, she is the most popular member of the new government.

Her economic team has vowed to push ahead with populist policy promises that helped her party sweep the July 3 election -- from sharp minimum-wage increases to a cut in corporate taxes and increases in village development funds.

The risk now is that a spotlight on Thaksin could shift the focus away from her plans and possibly provoke the generals who worked to oust Thaksin five years ago.

In recent days, journalists have bombarded her with questions about Thaksin, while Thursday's newspapers were filled with unflattering columns, some of which questioned whether she would really serve the country as promised.

"Aiding Thaksin already, PM?," read one headline in the Bangkok Post. "Pretty woman takes first misstep" was another in the same daily.

"Government  hard at work to bring Thaksin back" was the headline in one political column in the Nation newspaper, a day after a front-page banner blared "Ploy to bring back Thaksin." Another read: "Thaksin should let his sister at least start working."

Her troubles began on August 9 when she announced the name of Thailand's new foreign minister -- a distant relative loyal to Thaksin with no diplomatic or ministerial experience.

Surapong Towichukchaikul did himself no favors when he called a meeting two days later -- his first as a minister -- with a Japanese diplomat to request a visa for Thaksin to visit Japan. His request was granted.

Opposition politicians sharply criticized the issuance of the visa, calling Thaksin a fugitive from justice.

The previous government stripped him of his Thai passport. He is known to travel on passports issued by Nicaragua and Montenegro having been granted citizenship in both countries.