A Malaysia Airlines plane was forced to make an emergency landing at Melbourne's Tullamarine Airport less than 30 minutes into a flight after a man tried to enter the cockpit, claiming to have explosives.
One of the passengers on board told SBS World News he believed the man was carrying an "electronic frequency" device.
Flight MH128 from Melbourne to Kuala Lumpur returned to Melbourne shortly after takeoff late on Wednesday "after the operating captain was alerted by a cabin crew of a passenger attempting to enter the cockpit", the airline said.
In a statement, the airline stressed "at no point was the aircraft 'hijacked'".
"Safety and security are of utmost priority to Malaysia Airlines," the statement said.
"Malaysia Airlines together with the Australian authorities will be investigating the incident. Affected passengers will be accommodated at hotels. They will be offered travel on the next available flight or on other carriers."
Police have said the man did not have an explosive device.
Officials of Malaysian Airline said the man is a Sri Lankan who live in Dandenong, Australia.