Malaysia's Prime Minister Najib Razak says, missing Malaysian airliner appears to have been deliberately steered off course after someone on board shut down its communications.

A week after the disappearance of flight MH370, Najib giving his first statement at a news conference in Kuala Lumpur yesterday confirmed reports that investigators believe somebody cut off the plane's communications reporting system, switched off its transponder and steered it west, far from its scheduled route.

Minutes after the Malaysian leader outlined investigators' latest findings, police began searching the house of the aircraft's 53-year-old captain for any evidence that he could have been involved in foul play.

The Malaysia Airlines Boeing 777-200ER vanished en route from Kuala Lumpur to Beijing in the early hours of March 8 with 239 passengers and crew aboard.

In view of this latest development the Malaysian authorities have refocused their investigation into the crew and passengers on board.