Investigations into severed wires in a Malaysia Airlines aircraft, the third such case in nearly a year, are focusing on the possibility of an inside job, police said Saturday.

The national carrier was found to be in full compliance with safety and security measures, raising the possibility of an inside job, a police spokesman told AFP on condition of anonymity.

Transport Minister Chan Kong Choy said late Friday: "We do not rule out the possibility of an insider job."

"I appeal to the police to leave no stone unturned, especially when they investigate from the angle of a possibility of an insider job," Chan was quoted as saying by the Bernama news agency.

Malaysia Airlines was this week forced to ground one of its Airbus A330 aircraft bound for Bangkok after engineering staff discovered that some wires in its cockpit had been severed.

The discovery made it the third such incident involving the airline since last year. The others were in a Perth-bound A330 on October 2 last year and a Boeing B777 destined for Bombay, India on November 26.

"When the aircraft was powered up during routine maintenance service, the A330 flight system showed a malfunction signal in the cockpit. Initial inspection showed that the wiring system could have been tampered with," the carrier said Thursday.

In previous cases, police questioned Malaysia Airlines employees but did not press charges against anyone. No possible motives for the apparent acts of sabotage have been publicly mentioned by airline or police officials. - AFP