
Sompong said his group planned to revive the disbanded Thai Rak Thai Party under a new name, which he refused to reveal.
He claimed that the majority of former MPs had remained loyal to the former ruling party and would seek re-election under its new banner.
Former Thai Rak Thai MP Kuthep Saikrajang said it was unfair for former opposition parties to launch campaigning activities while ousted politicians could not.
Kuthep warned the junta about a repeat of the 1992 Bloody May uprising if it insisted on favouring the military's puppets over other politicians.
"In 1992 the line was clearly drawn between good and evil parties, and look what happened when the military leaders sided with the evil," he said.