The petition, submitted yesterday to caretaker Senate Speaker Suchon Chaleekrua, claims Thaksin and his Cabinet had lost their status after Thaksin took six weeks leave from office on April 5.

The break, they said, amounted to a departure from office following Constitution rules.

"Thaksin's return was illegal because he had practically resigned from his premiership," caretaker senator Karun Sai-ngam said.

Earlier this month the same petition was rejected by the Administrative Court, which ruled that only the Constitution Court was empowered to judge if Thaksin was entitled to resume office following his break.

The Constitution also states that all ministers lose their status when the prime minister loses his job.

Thaksin relinquished the top office in early April, after the expiry of his government's term because of the House dissolution on February 24, thereby suspending his caretaker duties until a new government could come to power.

The caretaker prime minister ended his "break" from politics and resumed work last month.

Karun, Nirun Phitakwatchara, Chirmsak Pinthong and Kraisak Chonhavan were among the 29 senators who submitted the petition.

Most of them were among a group of 35 senators who had submitted another petition to Suchon, asking the Constitution Court to rule on whether the three remaining election commissioners should be disqualified as the election watchdog now lacked a quorum.

Suchon did not personally receive the petition at Parliament, sending Surapong Masawisut, the spokesman for the Senate Secretariat, to represent him.

Karun, who has accused Suchon of actively supporting Thaksin, was annoyed by Suchon's decision not to accept the petition personally.

He said Suchon should have accepted the petition to prove it would be passed on to the Constitution Court without delay.

Suchon said Karun had not made an appointment with him and that he had a schedule to follow which had taken him away from Parliament.