The French Polynesian opposition Tahoeraa Huiraatira Party says it doubts that the assembly has the means and power to hold an inquiry into the disappearance of several politicians three years ago when their plane vanished in the Tuamotu islands.
The widow of the former Fetia Api leader, Boris Leontieff, wrote to the interim speaker to ask for a fresh probe after failing to get a conclusive explanation for the plane's disappearance.
Five people, including three politicians, died in the crash but no plane was ever found.
The widow, Celine Leontieff, raised the matter amid revelations of espionage on behalf of the Tahoeraa president, Gaston Flosse.
An investigation has been reopened into the disappearance in 1997 of Mr Leontieff's media advisor, journalist Jean Pascal Couraud.
He was believed to have committed suicide until a former spy working for Mr Flosse last year claimed the journalist was kidnapped and drowned.
The Tahoeraa has now denounced what it calls manipulations to create a link between the two cases.
It also says it backs efforts to re-open the Leontieff case.
Mr Flosse has said claims of foul play in the case of the journalist's disappearance are the lies of the pro-independence movement.