Sorry, I am a bit late to answer. The company I have been working with is called Clearview Packaging in Auckland - http://clearviewpkg.co.nz/mainframeset.html . Since I have moved to Melbourne last year and restarting my business, I find that the boxes are not that expensive. Certainly better, than buying thousands! They mail as many as I want, whenever I want.
If anyone knows a better source in AU, please let us know.