MH370 could have been brought down by a stowaway who was hiding somewhere on the Boeing 777, an aviation expert has claimed.

Others have previously suggested pilot Zaharie Amad Shah crashed the plane after taking it off course shortly after taking off from Kuala Lumpur in March 2014 with 239 people on board.

But Philip Baum, editor of Aviation Security International, said experts should be looking into the possibility that someone sneaked on board to sabotage the flight.

He told the Independent: "I think a stowaway is a strong possibility, especially as no officials seem to want to even contemplate the possibility."

Baum believes the saboteur could have hidden underneath the floor or just behind the flight deck in a "hinged, self-closing access panel".

His magazine reported as many as 123 stowaway attempts have been reported internationally across 107 separate flights.

Many of them hid in the wheel wells but there have been other, more brazen attempts from those who tried to disguise themselves as cleaners or officials.

Meanwhile, a Malaysian report into the disappearance of the jet was rubbished by French investigators who claimed it ruled out an "act of madness" by the captain.

They branded the 449-page document, which did not give any concrete explanation as to what happened in March 2014, as "imprecise and ambiguous" amid claims of a cover-up.

Malaysia's government released its findings more than four years after the infamous jet went missing after performing a mystery U-turn shortly leaving Kuala Lumpur with 239 passengers on board.

It suggested the diversion from the planned route was likely made "under manual control" but extensive background checks on captain Zaharie Amad Shah and the crew found nothing remotely sinister.

Investigators also admitted they could not "exclude the intervention of a third party" but did not expand on what that could mean.

The report concluded that a lack of evidence, including the flight recorder, made it impossible to figure out why the plane changed paths and why communication with the plane was lost 40 minutes after take-off.

Unsatisfied with the findings, the Gendarmerie of Air Transport (GTA) has launched its own probe into the mysterious disappearance, according to Le Parisien.

It said the presence of four French victims - Laurence Wattrelos, his daughter Amber, 14, son Hadrien, 17, and the latter's girlfriend Yan - allowed it to conduct its own investigation.

The organisation was furious the Malaysians failed to look into the possibility the doomed flight was a "very sophisticated suicide operation".