Thanathorn Jungroongruangkit is calling on MPs from the dissolved Future Forward Party (FFP) to support students and other protesters staging rallies against the government.
Mr Thanathorn posted what he called his last message as leader of the dissolved party leader after the censure debate came to an end.
Mr Thanathorn urged backing for students and other people rallying for democracy, while he said he will continue political activities outside Parliament.
Parliament has been in recess since the debate ended with an easy victory for the government on Friday. MPs under the FFP banner have to find a new party within 60 days of Future Forward's dissolution on Feb 21. The party was disbanded and its executive members banned from politics for 10 years by the Constitutional Court for accepting 191 million baht from an "illegitimate source".
FFP has suffered from the defection of its MPs since then, as nine left for the Bhumjaithai Party and one departed for Chartthaipattana. The remaining MPs will unveil the name of the new party expected to be announced this week.
Mr Thanathorn said on Feb 21 after the party was banned he would lead the Future Forward Movement to launch political activities nationwide.
He called for flash mobs after the Election Commission in December petitioned the court to disband the party over the loan. The sudden gatherings — the latest one at Kasetsart University on Saturday — have intensified since the party was dissolved on Feb 21. They demanded the ouster of Prime Minister Prayut Chan-o-cha and the return of democracy.
On Nov 20 last year, the same court disqualified Mr Thanathorn as an MP after ruling he had failed to transfer his shares in a media company when he registered his candidacy for the March general election