Admiral Bannawit Kengrien, chairman of the National Legislative Assembly's special committee tackling the airport's problems, said the evidence showed Thaksin illegally endorsed a contract to allow Italian-Thai Development Plc to construct the airport even though it had been ordered by a court to undergo rehabilitation.

Bannawit and Prapan Koonmee, chairman of a subcommittee probing the contract to build Suvarnabhumi's passenger terminals, yesterday lodged a complaint with the Assets Examination Committee (AEC).

Prapan said the subcommittee found the Thaksin government had begun to do wrong things right from the start of the bidding process by appointing a committee to alter the construction design, bypassing the airport's board.

Thaksin also instructed the board to sign a contract without having the power to do so in order to favour the company that won the bidding.

They accused Thaksin and others of abusing their power and of collusion by violating the Bidding for State Projects Act 1999, causing Bt10 billion in damage to the state.

Prapan said that on the day the contract with Italian-Thai Development was signed, a court ordered the company to undergo rehabilitation. The law bans the government from signing contracts with companies that are in that position.

"I have documents which show that Thaksin signed his name ordering the board to hire this company," he said.

Prapan accused former transport permanent secretary Srisook Chandrangsu of illegally altering the contract that was checked by public prosecutors to favour contractors such as insurance firms, thus preventing the state from being able to claim compensation from the firms.

Apart from Thaksin and Srisook, former transport minister Wan Muhammad Noor Matha was also accused of being involved in the alleged illegal activities at the airport.

Bannawit said the AEC would investigate accusations involving the government's contract with King Power for the right to operate duty-free shops in the airport.

He said AEC secretary Kaewsan Atibodhi had suggested Airports of Thailand should recommend to the Transport Ministry that it cancel the contract with King Power and demand compensation.

In related news, AEC chairman Nam Yimyaem said yesterday he had signed an AEC complaint to be lodged with the Crime Suppression Division against Thai Rak Thai Party caretaker leader Chaturon Chaisang.

Nam said if Chaturon apologised for his comment accusing the AEC of acting like a "kangaroo court", the AEC will decide whether or not to lodge a complaint.

"But if the complaint has already reached the police, the case cannot be settled out of court," he said.

Theerapat Srichaiya, one of Thaksin's legal representatives, turned up at the AEC yesterday to submit a letter to object to the appointment of members for an investigative committee to probe Krung Thai Bank's loan extension to the Krisada Mahanakorn group.