Police carry a piece of debris from an unidentified aircraft found in the coastal area of Saint-Andre de la Reunion, in the east of the French Indian Ocean island of La Reunion, on July 29, 2015

AFP/ Kuala Lumpur

 An MH370 families organisation said Wednesday it would not accept the Malaysian government's declaration that wreckage found on an island in the Indian Ocean came from the ill-fated flight until more "conclusive" analysis is completed.

Voice 370, an international next-of-kin support group, also reiterated its suspicion over the Malaysian government's handling of the jet's disappearance last year, and called for any potential MH370 debris to be analysed by impartial authorities.

Malaysian Prime Minister Najib Razak said last Thursday that a wing part which washed up on the French island of Reunion had been confirmed by experts in France to be the first physical evidence that the Malaysia Airlines jet had met a disastrous end in the Indian Ocean.

"However, after one week, other experts have not concurred with the Malaysia declaration," Voice 370 said in a statement.

"Needless to say, most families have refused to accept the Malaysian verdict, and are awaiting a more definite and conclusive analysis," it added. 

The Boeing 777 vanished on March 8 last year with 239 passengers and crew, triggering one of aviation's greatest mysteries and history's biggest search operation, now focused on the southern Indian Ocean.

After the jet's disappearance, Malaysia's government and the state flag carrier came under intense fire from next-of-kin who accused both of fumbling their response to the disaster, being slow to release information, and a series of confusing or contradictory statements.

The Voice 370 statement said families "are apprehensive about the handling of the whole incident from day one by the Malaysian authorities.

"This led to families having doubts about their expertise, capabilities and intentions."

French authorities have not gone as far as Najib in confirming that the wing piece came from the plane, saying only that there was a "very highly probability".

"We the families of those on board MH370 would like to appeal that all debris be analysed at a reputable place with the appropriate expertise and equipment" including possibly the French government or authorities from other "advanced nations", Voice 370 said.