In one reverse for Pheu Thai, former prime minister Somchai Wongsawat – brother-in-law of party patriarch and veteran politician Thaksin Shinawatra – failed in his bid for a senate seat.
Senators were chosen not from political parties but to represent 20 different fields of work and life, including justice, education, public health, industry, arts and sports, the elderly and ethnic minorities.
In a significant change, the new senate – 50 members smaller than the outgoing version which was appointed by the ruling junta in 2014 – will no longer vote to approve the prime minister after an election.
The current senate played a crucial role after last year’s general election, blocking Pita Limjaroenrat – the leader of the party that won most seats – from becoming premier.
The government will also need approval from at least a third of the upper house for its plans to change Thailand’s constitution – scripted by the junta in the wake of its power grab.
Final results will be officially confirmed on Tuesday.