A Noumea-based French research ship has been despatched to French Polynesia where it is being used to try and find five politicians missing at sea since May.
They disappeared with their small aircraft in the Tuamotu islands while campaigning ahead of the territorial election.
The French news agency, AFP, reports that investigations have failed to explain where and why the aircraft disppeared.
The ship is looking at the area around Katiu atoll where the last signal was picked up of the Piper plane carrying opposition politician Boris Leontieff and a leader from the Marquesas islands, Lucien Kimitete.
The ship is looking in an area where waters are about 1-thousand metres deep although scientists say their sonars are unlikely to identify a small plane beyond a depth of 150 metres.
The latest sea search follows a request by the people of the Marquesas made to the French president, Jacques Chirac.