Thailand is prosecuting Facebook, Google, and Twitter over their failure to remove what authorities in Bangkok say are illegal posts.
Officials have also announced they would take action against individual users who have posted anti-monarchy comments on the sites.
“We’ve notified the companies and sent them warnings twice, but they haven’t complied with all the requests,” digital minister Puttipong Punnakanta told Reuters news agency.
He said the matter is now in the hands of cyber-crime police for prosecution.
Under the computer-crimes law, social-media companies can be fined 200,000 baht (RM26,500) for ignoring a court order to take down posts, and an extra 5,000 baht (RM650) every day until it is removed.
“It is the first time in Thailand that the computer crime law is exercised to prosecute the service providers. Charges will go to the parent company of all the organisations. The police will use Thai laws because the offences happened in Thailand. I believe the police can do it,” Puttipong said.
Calling for reform of the Thai monarchy is a perilous pursuit.
Thailand criminalises criticism of the royal family, and offenders can be tried in secret and given long prison sentences.
In August, Facebook blocked access in Thailand to a million-member group discussing the monarchy after the Thai government threatened legal action.
Access from within Thailand to the “Royalist Marketplace” group was blocked but the page could still be accessed from outside the country.
Facebook and Twitter have declined to comment on the case, and Google has yet to respond to requests for comment.