Future Forward Party leader Thanathorn Juangroongruangkit said the Constitutional Court does not have the authority under Section 49 of the charter to dissolve his party, which has been accused of trying to overthrow the constitutional monarchy.
The law only says that judges can be asked to "consider handing down a verdict to stop such an act" if it has grounds, he said on Sunday.
Last Friday, charter court judges voted 5-4 to accept a petition filed by lawyer Natthaporn Toprayoon, who accused Mr Thanathorn and his party executives of trying to bring an end to the monarchy.
Mr Natthaporn pointed to the party's regulations, which he claimed were written to support the "constitutional democracy", which he said can be interpreted as a support for systems other than a constitutional monarchy.
"[FFP] supporters can be now relieved as the court does not have the power to dissolve the party," Mr Thanathorn said.
The FFP leader said he believes their concerns over a possible party dissolution reflect their lack of confidence in the Thai judicial system.
Mr Thanathorn also said he believes the allegation made by Mr Natthaporn is a means to dissolve any party that strongly opposes the military regime's attempts to prolong its hold on power after the general election.