Hi Rico,
I was recently in the airport of Auckland on my way back to Denmark. I got a box for free from a store in city, but it was too small for my bike, but it was the only size they had. I couldnīt use it, so I went to a small store in the airport, as far as I remember: "Pack and Security" - they are selling used bikeboxes and store boxes too untill you are leaving Auckland airport again. Their boxes didnīt fit to my bike (fenders and so on). I went to the counter of Quantas. They have new and strong boxes for 20 NZ$. I bought one and my bike arrived in Copenhagen together with me free of charge.
Per