The Central Administrative Court will on Wednesday rule on a request to freeze fare increases for Bangkok and inter-provincial buses, pending a study of operating costs.
Srisuwan Janya, president of his Association for the Protection of the Constitution, told reporters of the court's schedule after testifying against the fare hikes, which took effect on Monday.
The court sought details of the operating costs of passenger buses from state-run Transport Co and the Bangkok Mass Transit Authority, which supervises bus services, he said.
The fare increases were unfair to consumers because most bus operators made profits, Mr Srisuwan said.
Acting BMTA director-general Prayoon Chuaikaeo said the court had not ordered that the fare increase be postponed. The BMTA would obey the court's order.