Malaysia Airlines was forced to ground one of its Airbus A330 aircraft after engineering staff found possible tampering with the wiring system, the national carrier said today.

The grounding yesterday was the third such incident involving the airline since last year. The others involved an A330 bound for Perth, Australia on Oct 2 and a Boeing B777 destined for Bombay, India on Nov 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.

Police report lodged

Malaysia Airlines said a police report had been lodged and it was assisting in the investigations.

The Star newspaper said the Airbus was bound for neighbouring Thailand's capital Bangkok early yesterday.

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.

In the latest incident, the airline said a check revealed that wires under an instrument panel located under the captains seat had been cut.

It occurred despite increased security around parked aircraft at the ultra-modern Kuala Lumpur International Airport opened in 1998.