Breaking his long silence, Ahmed Seth, the youngest son of Captain Zaharie Ahmad Shah, who was piloting the Malaysia Airlines flight MH370, has denied that his 53-year-old father has any hand in the disappearance of the aircraft.

Rejecting the latest allegations against Shah that he could have been on a suicide mission either due to his personal problems or political inclinations, Seth told the Malaysian daily New Strait Times that he knew his father better.

"I've read everything online. But I've ignored all the speculation. I know my father better. We may not be as close as he travels so much. But I understand him," the pilot's 26-year-old son said.

Shah's personal life is being closely studied by investigators amid speculation that he was "terribly upset" over his separation from his wife Faizah Khan and could have taken the plane, with 239 people aboard, for a "last joyride".

Shah's flight simulator is also being examined by forensic experts for clues.

Shah's son was said not to have shown any resentment towards those who allege that the pilot could have turned rogue pilot.

Seth said: "Now, we are just waiting for the right confirmation [for the wreckage or bodies]. I will believe it [that there are no survivors] when I see the proof in front of my eyes."

The family, including the pilot's three children and wife have not spoken to the media despite widespread conjecture over Shah's alleged role in the plane's disappearance.

The pilot's daughter, Aishah Zaharie, who lives in Melbourne, has also returned to Malaysia to join her family.

Meanwhile, the hunt to find the plane's wreckage has moved into a remote area of the southern Indian Ocean as thunderstorms are expected later threatening to halt the search.