An unprecedented "republic" hashtag went viral on Thai social media Friday as pro-democracy activists vented their frustration at delays to constitutional reforms they blame on the kingdom's premier.
Thailand has seen near-daily protests for the past two months, calling for reform of the monarchy and the resignation of Prime Minister Prayut Chan-O-Cha, a former army chief who led a 2014 coup.
Lawmakers had been expected to vote on constitutional changes overnight Thursday but these will now be further scrutinised by a parliamentary committee.
More than a thousand people rallied outside parliament as junta-picked senators and members of the ruling coalition made the decision.
The protesters accuse the government of trying to "buy time", a claim Prayut rejected on Friday.
He said some of the proposals were unacceptable to many Thai people and parliament's decision reflected that, denying he had masterminded the move.
"The Prime Minister did not order it," he told reporters.
The hashtag #RepublicofThailand was trending on Twitter in the kingdom and had garnered 865,000 tweets by early Friday evening.
King Maha Vajiralongkorn sits at the apex of Thai power, supported by an arch-royalist military and the kingdom's billionaire clans.
The royal family enjoys support from mostly older conservatives and Thailand's monarchy is protected by one of the world's toughest royal defamation laws.
The ultra-wealthy monarch spends much of his time in Europe, but he was in Bangkok Thursday to mark Prince Mahidol Day, laying a wreath at his grandfather's statue.