Air Chief Marshall Chalit Pukbhasuk, the head of the air force and one of the military commanders who toppled the billionaire prime minister, said an assets freeze was under consideration.
Thaksin, the telecommunications tycoon-turned-politician, is currently in London, where he arrived from the US after being overthrown in last Tuesday's bloodless coup.
Thailand's revered monarch gave the country's military leaders his formal backing for the coup on Friday.
General Sondhi Boonyaratkalin, the coup leader and army commander, and other military leaders stood at attention in white uniforms in a nationally televised ceremony as a statement from the palace was read aloud at army headquarters, recognising Sondhi as head of the ruling military council.
Sondhi then kneeled and bowed before a shrine with a framed photo of the king, in a show of respect for the monarch.
Thaksin says he will not challenge
the military takeover
Under criticism from some states for the coup, the military has now moved to appoint a civilian interim prime minister within two weeks.
Late on Thursday, the Council for Democratic Reform under Constitutional Monarchy - as the ruling body is called - sacked four senior police officers with close ties to Thaksin and was holding three ministers of the deposed government in custody. Other detentions are expected.
Chalit said the generals were considering at least five candidates for prime minister, but he declined to reveal names.
"The new prime minister is likely to be a legal expert because he has to implement constitutional reforms, while his deputies can oversee economic affairs," he said.
The military government has also expanded the powers of the national police chief, which will make it easier to prosecute Thaksin and other members of his government.
Thailand's auditor-general said that she would be ready to complete at least one long-standing corruption investigation within days.
According to The Nation newspaper, the military council is to set up a six-member committee to investigate the assets of Thaksin and his family, along with those of many former cabinet members.