A Malaysia Airlines flight from Melbourne to Kuala Lumpur returned to the airport 20 minutes after taking off last night after a passenger reportedly threatened to blow up the plane with a bomb.

The man attacked an air hostess shortly after take-off and attempted to enter the cockpit. Witnessed said he shouted: "I'm going to blow up this plane."

The suspect was tackled by passengers and crew members and tied up with seat belts and makeshift handcuffs as the plane turned back to Melbourne airport.

Andrew Leoncelli, a former AFL star who was on the plane, told the Sydney Morning Herald the man was carrying a large black cylindrical object which looked like speaker with an on/off switch.