The New Zealand Civil Aviation Authority (CAA) has blamed mobile phones for at least two incidents in which aircraft made sudden uncontrolled movements mid-flight.
In its latest newsletter the CAA said both incidents were examples of possible electronic interference with aircraft electronic systems.
The authority said an aircraft preparing to land at Wellington airport last Christmas Eve unexpectedly turned right and climbed while approaching the airport. A passenger's mobile phone is believed to have been the cause.
No fault was found with the plane and two following aircraft reported no problems with the instrument landing system. The possibility of ground interference was rejected.
In another incident, an aircraft cruising on autopilot suddenly rolled 30 degrees after a mobile phone rang in a bag in the cockpit.
The CAA did not release the name of the airlines or the type of aircraft involved.
Mobile phone use on planes is banned in New Zealand and punishable with a fine of up to $NZ1,250 ($A1,019) for an individual and $NZ7,500 ($A6,120) for a company.