Tianjin Airline is stopping service to AKL from March 2019 as well. Is it a because Air NZ is winning the game, or a slow down in the tourism sector overall? That's worth a moment of thought. Maybe it's doing more harm to AIA, than AIR.
Bear in mind that AirNZ is looking after the line check and ground service for the Hong Kong Airlines birds in AIA. So that's a revenue drop when HKA cuts back their service.