The Election Commission says it will monitor electronic media around the clock to stop any attempt to "sabotage" the Aug 7 referendum by opponents of the draft constitution.
The warning came just two days after 17 senior Pheu Thai Party figures posted comments on Facebook that were highly critical of the draft charter, saying they would vote against it.
Speaking on Friday in Chon Buri, election commissioner Somchai Srisutthiyakorn said the EC, the Technology Crime Suppression Division and the Information and Communication Technology Ministry would form a working group to monitor the spread of "rude, false and provocative messages" via electronic media to influence voters.
The surveillance would be serious because electronic media would be the main battlefield of opinion in the run-up to the referendum, Mr Somchai said. He said he did not expect any active wrongdoing in terms of physical demonstrations in public places.
"The working group will be looking for wrongdoing via electronic media around the clock," he said. "When rude, untrue or provocative words that will influence voting in the referendum are spotted on electronic media, we will take legal action right away."
The referendum law calls for jail terms of up to 10 years and a fine of up to 200,000 baht as punishment for such wrongdoing.
Senior figures in the military government, who rarely miss an opportunity to accuse Pheu Thai politicians of stirring up trouble, earlier dodged questions about how the apparent violation of the law would be dealt with. They said it would be up to the EC to decide.
Mr Somchai assured the general public that they could comfortably comment on the draft charter and had the right to do so, as long as their expressions were not rude, untrue or provocative.
Meanwhile, leaders of the red-shirt United Front for Democracy against Dictatorship (UDD) said they would proceed with establishing their anti-referendum fraud centres although the government has opposed the movement.
Election commissioner Boonsong Noisophon said the EC would not certify the centres because such organisations must be politically neutral.
Everyone knew whether the UDD was politically impartial or not, he said, referring to the political interest group allied with Pheu Thai and fugitive former premier Thaksin Shinawatra.