The Pheu Thai Party has asked the National Broadcasting and Telecommunications Commission to look into programmes that make insulting remarks about Prime Minister Yingluck Shinawatra.
Supporters say the speech by Prime Minister Yingluck Shinawatra to a democracy forum at Ulan Bator last Monday was a defence of Thai democracy, while critics say it was a blatant whitewash of big brother Thaksin.
The party wants the NBTC, the national broadcasting regulator, to strictly monitor the content of TV and radio programmes that defame and unfairly rebuke "the national leader", said deputy party spokesman Anusorn Iamsa-ard.
He said the party was ready to listen to reasonable criticism but if it consists only of inappropriate and libellous remarks, it would take legal action against critics.
Ms Yingluck has become a target for severe attacks since delivering a controversial speech to a democratic conference in Mongolia late last month.
The premier expressed disappointment with the 2006 coup that toppled the government of her brother Thaksin and accused independent organisations, established under the 2007 coup-engineered charter, of abusing their authority.
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However, her speech raised doubts about whether she was trying to whitewash Thaksin, who is accused of abuse of power during his administration, and omitted certain information concerning political conflicts between pro- and anti-Thaksin groups.
Among the critics is Thai Rath cartoonist Somchai Katanyutanan, known by his pen name "Chai Ratchawat".
On his Facebook page the cartoonist wrote of Ms Yingluck: "Please understand prostitutes are not evil women. Prostitutes just sell their body but an evil woman sells the nation."
He is facing charges, including defamation and violation of the Computer Related Crime Act, following a complaint lodged on Friday by Ms Yingluck's lawyer.
Yesterday, the premier used her weekly TV programme to defend her speech. She said she told the 7th Ministerial Conference of the Community of Democracies of her intention to protect democracy and prevent any undemocratic actions from harming Thailand.
The ministerial conference had strongly criticised the 2006 coup and was well aware of the Thai political situation, said Foreign Minister Surapong Tovichakchaikul, who accompanied Ms Yingluck to Mongolia.
He said the Foreign Ministry intends to use other international forums as a channel to promote democratic development in Thailand.