Red-shirt protesters of the Radio Broadcasters for Democracy movement submitted a letter to the senate speaker at parliament on Wednesday calling for the removal of five of the nine Constitution Court judges.
The letter was accepted by Surachai Liangboonlertchai, the first deputy senate speaker, on behalf of Senate Speaker Nikom Wairatpanich, who is on an overseas trip.
In the letter, five leaders of the movement indicated their intention to petition for the removal of five judges of the Constitution Court, with the support of at least 20,000 names as required by the law.
The five judges they named for impeachment are Jaran Pakdithanakul, Charoon Inthacharn, Supot Khaimuk, Nurak Mapraneet and Chalermpol Ek-uru.
The red-shirts accused them of abuse of power, abuse of the law and serious breaches of moral principles and ethics in accepting for consideration a senator's petition against 312 lawmakers who proposed a bill to amend section 68 of the constitution.
The five judges voted to accept the petition, and the other four voted against it.
The protest leaders said they would gather up to 50,000 names and forward the list to the Senate Speaker in 15 days for further action.
Mr Surachai said that the petition with the names of the supporters, when submitted, would be verified and then forwarded to the National Anti-Corruption Comission (NACC).
The leaders of the protest also issued a statement of support for members of parliament who proposed bills to amend the constitution, and encouraged them to monitor the conduct and performance of the Constitution Court judges.
The red-shirts moved from in front of the Constitution Court at the government offices complex on Chaeng Wattana road in the morning and arrived at parliament before noon.
About 200 policemen were deployed in the area to maintain law and order.