The group, led by Supaphorn Nam-montri, claimed that the Cabinet had not considered an arbitration ruling on contractual disputes prior to revoking the company's TV concession, and thus violated the contract between the PM's Office and the private firm.

About 200 shareholders held a meeting at Kasetsart University to prepare their bid to fight the PM's Office in court.

Last month, the PM's Office retracted the concession after the company said it did not have the money to settle a huge sum of unpaid concession fees and fines.

iTV's broadcasting business was then transferred to the Public Relations Department under the PM's Office and renamed Thailand Independent Television (TITV).

The company was majority-owned by the family of ousted premier Thaksin Shinawatra before it was sold to Temasek Holdings of Singapore in January last year.

The Cabinet last Tuesday approved the station turning into the country's first public service channel.

Supaphorn, one of the 9,000-plus small shareholders of iTV, said the group would hold a rally in front of the Stock Exchange of Thailand on Wednesday because the market authority had not acted to protect investors during the government-iTV dispute.

"While the Supreme Administrative Court was in the process of issuing its decision on the iTV case, the SET never posted any sign [on the stock] to warn investors," she said.

Minor shareholders are also considering taking legal action against iTV management for negligence in letting the company lose its concession.

"More than 50 per cent of small shareholders are long-term investors, believing that a government concession is a safe investment, but it's not. And this government is an interim administration. It shouldn't have taken such a step [against iTV]," she said.