Thai Prime Minister Thaksin Shinawatra has said he will step aside after failing to win a clear mandate in a general election on 2 April.
The BBC News website looks at some possible successors.
Deputy Prime Minister and Commerce Minister Somkid Jatusripitak has emerged as a front-runner. A respected business leader, he has also served as finance minister in Mr Thaksin's cabinet.
An economics graduate, Mr Somkid gained a doctorate in business administration in the US.
He has served as a financial advisor to Mr Thaksin's telecoms business and is respected within the business community.
On 3 April, Mr Thaksin said during a live TV interview that he had identified four possible candidates to succeed him and he named two, one of which was Mr Somkid.
The Bangkok Post has called Mr Somkid the "most likely" person to take over, with key party support.
But he has not confirmed he is looking for the job. "Thai Rak Thai is a big party and there are many senior members," he said when asked for his views.
A former deputy prime minister and interior minister, Bhokin Bhalakula is Mr Thaksin's top legal expert and the outgoing speaker of parliament.
He is said to have played a significant role in Mr Thaksin's political strategy in recent months.
Mr Bhokin studied law in France and was a university law lecturer before entering politics. He has served as a judge on the Supreme Administrative Court.
As interior minister during Mr Thaksin's first term, he was involved in the 2003 crackdown on drugs which drew criticism from human rights watchers, but he was praised for his role in tsunami relief work.
Mr Bhokin was the second candidate Mr Thaksin named as a potential successor during his TV interview on 3 April, but The Nation newspaper says he is not popular among the Thai Rak Thai party leadership.
Agriculture Minister Sudarat Keyuraphan is one of Thailand's most prominent female politicians.
A loyal ally, she helped Mr Thaksin found the Thai Rak Thai party in 1998 and has also served as health minister under him.
She ran unsuccessfully as Thai Rak Thai's candidate for Bangkok governor in 2000.
But Ms Sudarat has suggested she may take a break from politics and is not a potential candidate for the prime ministership.
"I can tell you now, I'm not cut out for the job," the Bangkok Post quoted her as saying on 5 April. "There are only two names on the list."
Surakiart Sathirathai has gained a higher profile since Thailand backed him to be Asia's candidate for the post of United Nations secretary general.
Mr Surakiart served as foreign minister from 2001 to 2005, before becoming a deputy prime minister.
A former academic, Mr Surakiart has a law degree from Harvard University and taught law in Bangkok before entering politics, becoming a deputy leader of the Thai Rak Thai party.
The Nation quoted a party source as saying Mr Surakiart could be one of the two as yet unidentified candidates Mr Thaksin has in mind.