MH370 AirAsia X, the long-haul arm of budget carrier AirAsia, has suspended a pilot for comments he made online on the search for missing Malaysia Airlines flight MH370, pending a domestic inquiry.

"AirAsia X senior first officer has been suspended pending investigation as company policies were broken in Facebook posting," group chief executive officer Tony Fernandes said in a tweet last night.

Air Asia X chief executive officer Azran Rani Osman added that the first officer contravened a "specific directive" not to publicly comment on the ongoing search.

"(There is a) specific directive to our crew on public comments on MH370. (There is a) duty of care not to be hurtful," he wrote in response to Fernandes' tweet.

When contacted, Air Asia X said that it would not be releasing any further details on the matter.

The AirAsia top guns' comments come as several blogs circulated a picture of an AirAsia X pilot's Facebook post where he criticised the government for declaring that MH370 fell into the Indian Ocean.

"For f**k's sake lah... Is there any concrete proof that MH370 has indeed crashed?! It's not right to simply assume when you have no evidence to back up your claims!

"(The) supposed debris... isn't even confirmed to be from the plane yet! Show us the proof then tell us MH370 has crashed.

"Till then, stop hiding facts! It's obvious to even a blind man that there (are) tons of info the government definitely knows and isn't sharing yet!" the posting reads.

The pilot, whose identity is being withheld by Malaysiakini pending his comments, has disabled his Facebook account. It earlier showed that he is a senior first officer at AirAsia.

His other social media accounts show him in a pilot's uniform and features a video about his love for flying, which also includes various shots of AirAsia planes.

On Monday night, Prime Minister Najib Abdul Razak said that MH370 "ended" in the Indian Ocean, far from any possible landing strips, based on calculations using satellite data.

MAS chief executive officer Ahmad Jauhari Yahya said that MAS concludes that there are no survivors as it the area it likely fell is thousands of nautical miles from any land mass and is one of the roughest seas in the world.

"It has been 17-18 days," he told reporters despondently.

Air traffic controllers lost contact with the plane at 1.30am on March 8. Satellite data shows that the last "ping" from the air craft was eight hours later, putting it at the southern Indian Ocean.

It had enough fuel to fly for eight hours, and had departed from KLIA at 12.41am.

No debris has been found.