Thai PM Surayud Chulanont has said he might hold elections to restore democracy earlier than planned.
Many Thaksin supporters may vote against the new constitution
The poll could be held on 25 November, if a post-coup constitution is approved in an August referendum, he said.
On Tuesday, Thai police said they wanted to question exiled former PM Thaksin Shinawatra over alleged graft.
There were initial reports Mr Thaksin would be required to go to a Bangkok police station. But police later said his lawyers could appear on his behalf.
They want him to answer questions about allegations he secretly concealed assets in a family-owned property company.
Thailand has been in political turmoil since the military led a coup against Mr Thaksin and his government while he was out of the country last September.
Since then, the billionaire former prime minister has remained abroad, living mostly in London.
He is being investigated by the new Thai authorities on allegations of corruption, principally over the controversial sale of his family's telecoms firm, Shin Corp, in January 2006.
Earlier this month, his party, Thai Rak Thai, was found guilty of violations during the April 2006 elections, and ordered to be dissolved.
Mr Thaksin and more than 100 other senior Thai Rak Thai officials were banned from politics for five years as a result of the court decision.
Prime Minister Surayud confirmed plans to move the election to November after meeting election officials on Wednesday.
"There is a possibility that this can be done if the constitution passes the national referendum on 19 August," he said.
Mr Thaksin has stayed away from Thailand since the coup
The chairman of the election commission, Apichart Sukhagganond, told reporters that the final draft constitution could be ready by 6 July, to be put to a referendum in August.
There is no guarantee that the constitution will be approved, analysts say.
Thai Rak Thai has urged its supporters to vote against the document unless key changes are made.
Prime Minister Surayud said earlier this week that a referendum and election needed to be held as soon as possible to ease political tensions and restore confidence for overseas investors.
But the political fall-out from the coup is unlikely to disappear any time soon, analysts say.