I suppose it really is a country of two halves with the North and South Island, but during my whole time on South Island I was really under the impression that the whole country was run by the Department of Conservation (DOC).
Their green and yellow signage is everywhere for designating reserves, camping areas, and providing education for tourists. Our tour of south island was based on the locations of the DOC campsites, especially the free ones. We were always honest with the sites requiring self-registration and use of the honesty box. After all, the DOC really made our time on South Island fantastic.
At times it was like a geography field trip, or a lesson in geology, other times we were learning about glaciers or bird life. Thanks to the DOC we're better educated (or at least re-educated after forgetting all this stuff from GCSE geography!). The great thing is that all this is effectively provided for free and our only real expenses were campervan, food and petrol.
Unlike Australia we could stay on budget, and we felt like free-roaming adults again with the DOC's open, educational, and positive attitude towards tourism, which in turn, encouraged responsible behaviour on our part. It seems almost unfair to mention the one time capitalism did show its ugly face in Oamaru, where one business had sectioned off a stretch of coastline and was charging an entrance fee (were they Australian?) to watch the Blue Penguins come ashore. This was completely ridiculed by the free roaming Blue Penguins that we saw nearby and the fantastic Yellow-Eyed Penguin colony just down the road (managed by the DOC) so we were very highly rewarded for not parting with our cash on this occasion.