Varawut Silpa-archa was elected leader of the Chartthaipattana Party on Monday and immediately set a target for his party to win 30 seats in the House of Representatives at the coming general election.
Mr Varawut was elected by the party's general assembly, replacing his older sister Kanchana Silpa-archa who resigned on Sept 20. He was previously chairman of the party's policy and strategy committee.
Five deputy party leaders were also elected. They are: Anurak Jureemat, a Roi-Et MP; Anucha Sasomsap, a former Nakhon Pathom MP; Wichit Pornprutiphan, a former Phetchabun MP; Samphan Paenpat, a former Nakhon Si Thammarat MP; and Yuthapol Angkinan, an adviser to the minister of natural resources and environment.
Prapat Pothasuthon remains the party secretary-general.
Ms Kanchana said she hoped Mr Varawut would strengthen the party with his ability to win support from both old and new members, and raise the party's flag in all regions - as had their late father and former prime minister Banharn Silpa-archa.
Mr Varawut said the party was in the process of selecting candidates for the general election, tentatively scheduled for May 7. Party members had visited people in their areas to take note of their grievances, he added.
The party's aspiring candidates had been told to strictly follow the election law to avoid getting the party in trouble.
He said the party aimed to win about 30 House seats.
"We have not talked about the party's prime ministerial candidates. The matter may be raised later, at an executive committee meeting this week," Mr Varawut said.
Sources said Prime Minister Prayut Chan-o-cha sent flowers to congratulate Mr Varawut, so did the Palang Pracharath, Prachachart and Pheu Chart parties.