"The vote should not take place before the completion of the vetting process for job qualifications," caretaker Senator Sunthorn Chinda-in said.

Sunthorn said he foresaw no possibility of the vetting being completed before Tuesday, adding that the upper chamber would then need three days notice before casting votes on the matter.

He said the vetting process was on track to be completed within the 20-day deadline although Suchon appeared to be trying to rush the vote ahead of the agreed date.

The upper chamber originally resolved to vote on the appointment around September 4 before Suchon made the bombshell announcement about the Royal Decree setting the session's closing date for Thursday.

The minority senators said Suchon was using underhanded tactics by delaying the announcement about the closing date.

Speaking in his defence, Suchon said he knew the closing date in advance but could not inform his fellow senators pending the publication of the Royal Decree in the Royal Gazette.

The government was responsible for the delayed publication, he said, distancing himself from the issue.

He also stated that he had no intention of forcing the vote ahead of the schedule, saying the vote and the closing date were separate issues.

The Senate could decide either to stick to its scheduling or revise it as it deemed necessary, he said.

The difference between the closing date and the voting schedule was about two days, hence the matter should not be blown out of proportion, he said.