Tramping in New Zealand
Tramping (a.k.a.Hiking) is a popular way to see New Zealand. Most National Parks in New Zealand are administered by the Department of Conservarion. The DOC offices and web site are very useful for providing you with all the information you will need.
Entering New Zealand bush can be extremely dangerous if you are under equipped. The weather can change without warning. If you don't have the right equipment you may die from hypothermia. NZ Mountain Safety Council has some information online but I recommend you visit a DOC office before setting out on a trip.
Many of the national parks have basic accomodation called huts, which range from a basic roof over your head with large bunk spaces and a "long drop" toilet, to the deluxe huts on the Milford Track with individual bunks and flush toilets (one of which has electric lighting).
There are two classes of huts. Back country huts and great walks huts. The back country huts are very basic but also very cheap. You can get an annual back country hut pass for $65, whereas the great walks huts range in price from $10 up to $35 per person per night.
Most of the back country huts are often maintained by tramping clubs on a volunteer basis whereas DOC tend to maintain most of the great walks huts.
Some people feel inclined to bring a tent. There are tent sites in some of the low lying areas but most people will find that the hut system is roughing it enough. A tent is great if you want to camp next to your car but it's not really what you want for tramping.