Forty three private hospitals have been summoned to clarify why they failed to submit information on the actual costs and their listed prices of drugs, medical supplies and medical services to the Internal Trade Department by the July 31 deadline.
Whichai Phochanakij, director-general of the department, said that 43 of 353 private hospitals have been ordered to explain why they failed to comply with the order.
The information on medical costs and set prices will be updated on the department's database so the public can compare prices and make choices.
According to Mr Whichai, once the prices have been compiled and adjusted, the department will also publish the information on its website and via QR codes.
The move is in response to growing complaints about overly expensive drugs and services at privately-run hospitals.
Mr Whichai warned of legal action against those who ignore the summons.
Those failing to respond to a summons will be subject to a three-month jail term and/or a fine of 5,000 baht while those failing to provide the information face a one-year jail term and/or 20,000 baht fine plus an additional daily fine of 2,000 baht until they comply.
"The legal division is sending out letters to 43 private hospitals asking them to explain why they did not provide the required information by the deadline. We gave them sufficient time," he said.
The requirement for the hospitals to declare their costs and prices was announced in May.
In April, Mr Whichai cited a survey that found that some private hospitals were overcharging at rates ranging from 30% to 300% above actual production costs.
Meanwhile, the Trade Competition Commission is scrutinising the business structures and strategies of healthcare providers, especially in the private sector, to determine whether they are engaging in free and fair competition.
Sakon Varanyuwatana, chairman of the commission, said those found to have colluded in pricing will be fined under the 2017 Trade Competition Law.
The law permits fines of no more than 10% of revenue generated in the year of the offence, he added.
"We are looking into the healthcare industry in fine detail to understand the business behaviour and determine whether practices are against the law," he said.