Suvimol Phumisingharaj said there would be an overlap between the old and new Senates as the former remain as caretakers until their successors can start working, which according to law is only after they take the oath of office.

The Finance Ministry has said the outgoing senators will be paid for the full month of April. New senators whose election is endorsed by the Election Commission will receive salaries calculated from the day they were elected.

She said the Senate Secretariat had prepared an introductory programme for the new incumbents. They will also get their own lounge at Parliament and a new office on nearby Sukhothai Road that has been leased for one year from the Chat Pattana Party for Bt2 million a month.

Election Commission secretary-general Ekachai Warunprapha said 682,553 people voted on Thursday, the first day of advance voting in the senatorial poll. Of these, 49,057 cast ballots outside their constituencies while 633,496 voted in their constituencies.

He said ballot boxes would be sealed with many staff signatures and kept safely at police stations. The procedure of moving the boxes could be examined at every step.

Former Senate Speaker Suchon Chaleekrua, who cast his advance ballot yesterday, said the high number of voters showed there was much enthusiasm for the senatorial election. The turnout reflects the fact that the public understands the purpose of political reform, he said.

"The people understand we need the Senate as a check and balance to government. It's possible the [recent] MP election encouraged people to vote, fearing they would lose their rights by not voting last time," Suchon said.

Meanwhile, the chairman of the Nakhon Ratchasima Election Commission office yesterday insisted that a fresh Senate election be held in the province because of the number of complaints of cheating during the advance voting.

Paiboon Makwiman said the commission had received at least one telephone report of election cheating every 15 minutes. The allegations include vote-buying, providing food and drink to voters, sponsoring tours and activities for voters, and campaigning alongside MP candidates.