My advice is to just do it. The worst that can happen in reality is they take the stuff off you. My wife brought back from PF some PPD that they wouldn't ship out of the US of A. She was on holiday with a friend and they shipped it to her daughter's place in NJ.
Not a thing was said at customs. It was clearly labelled if they had stopped to do a random search.
Having said all that you can get basics in NZ just like here (Oz). It's not as good as the old days but then, where is for photo supplies?
Hey! How about some caffenol? Instant coffe, pool pH raiser (NaCO3) and ascorbic acid or Na ascorbate?
Be prepared to explain. That's it.