The four candidates of the law and judicial profession group, which had 83 candidates at the provincial level of the senatorial poll, vowed to file complaints with the police and the Election Commission.
The four protesting candidates were identified as Thanesuan Mahathaninwong, Sunthorn Suptantikul, Boonyarat Pattanamahin, and Thukchai Kanchanaseth.
The EC officials at the Bangkok election venue announced that three candidates of the group had got four votes each and were considered the first three to move into the second round of voting.
The officials said 13 other candidates of the group had an equal number of three votes so they would decide by a draw of lots the fourth and fifth place. The four protesting candidates were not among the 13 candidates who got three votes.
The four protested and demanded a recount of the ballots. They claimed they had heard ballot counting officials announce that they had got three votes but the official in charge of marking the board failed to mark the third vote.
The officials refused to recount the ballots, saying the four had not argued during the counting and they had not made any formal appeal.
Manwika Thongprasert, director of the Bangkok election organising committee, said the EC had instructed her organising committee to proceed with the drawing of lots among the 13 candidates and asked the four to leave the room.
Thanesuan told a press conference after leaving the room that the election process was not fair so they could submit a petition to the EC Office later.