A Perth-bound Malaysia Airlines plane grounded this week after its wires were found cut could have been the subject of sabotage, and police are not ruling out "an inside job", a report said today.

Malaysia Airlines said in a statement late yesterday that two hours before its scheduled departure to Perth in western Australia, its engineers conducted a mandatory pre-flight check which showed a malfunction signal in the cockpit when it was powered up.

"(It) was not released when pre-departure checks indicated inoperable wiring on board," the carrier said.

"Upon further inspection, it was learnt that there could be a possible security breach and the police were promptly notified," it said.

The Malay-language Mingguan Malaysia quotes a police source as saying that it was sabotage and did not rule out the possibility that it was an "inside job" by someone with knowledge of airplanes.

Initial police investigations also show that the plane had suffered massive damage which could cause it to lose control if allowed to fly, the source said.

"What's certain is that the damage was quite severe and now we are focusing on who is responsible for this," the unnamed source was quoted as saying.

If the malfunction had not been detected, it would have caused a disaster, he said.

Routine inspection

At least seven bundles of wires were on Thursday found cut on the A-330 aircraft, including those under an instrument panel located under the captain's seat.

The aircraft had arrived at the Kuala Lumpur International Airport on October 1 from Singapore and was later sent to the maintenance bay for a routine inspection.

A replacement was deployed following the discovery of the malfunction.

"There were some discrepancies in the aircraft's systems," said the carrier's corporate services senior general manager Mohamaddon Abdullah.

"We do not compromise on the safety and security of our passengers and aircraft," he said.

"The matter is now in the capable hands of the police investigating team with whom we are working very closely."