The basic equipment is a food drier.
The pioneer NZ food drier was the Harvest Maid. They were taken over by EZIDRI and are available under that name through Ralph Roberts Electrical in Takapuna, and (I think) Magness Benrow, in the Auckland area, but don't even bother trying Noel Leeming, Farmers, etc, who tend to regard people who use them as food geeks and therefore likely to be unprofitable.
EZIDRI and Harvest Maid components are fully interchangeable.
You can often pick up a Harvest Maid on Trademe for $50-$150, depending on the use it's had and what accessories come with it. Make sure you get the FD1000 model. We were given one of these beauties, an old and well-used one, complete with a raft of accessories, only to have the motor give up on us after about a year, and we have replaced it with an EZIDRI, (white, in the photo above) retaining all the bits from the earlier model (cream, in the photo above). The basic new EZIDRI retails at around $300.
For most purposes, you can probably get away with one of the smaller "snack-makers", but there are advantages to the temperature control and range available on the big one, especially when drying meat.
A basic EZIDRI Ultra FD1000 consists of the following:
Besides these, at the very least, you should get 5 mesh sheets (one is provided in the basic kit) and some solid sheets (one is provided.) You can, of course, lay out your food for drying directly onto the drying trays, but a mesh sheet intervening makes cleaning up afterwards a whole lot easier. The mesh sheet is easy to soak and scrub. The drying tray itself is not so easy.
The solid sheets are for use making fruit leather of which more elsewhere. I suggest you buy three of these as once you've sampled your first leather, you'll be a fan of these, and a basic recipe for leather uses about three sheets.
You may also consider a couple of spacer rings. These can be useful when drying such food as bananas, which sit up a little higher than most, or when you want plenty of space around the food for maximum air circulation .
In the field
Out tramping, our basic equipment is a couple of small Kovea gas cookers, that each pack into a small zip bag about 80 mm x 50 mm x 35 mm. (Incidentally, since they've been taken over by a larger outfit, I've had a number of negative reports about Kovea product from people I've pointed in that direction, so caveat emptor.) We have a couple of aluminium bowls that double as plates at mealtime, but also as vessels for soaking vegetables beforehand. We have a 2 litre billy, and we have a couple of large mugs, one (very large) stainless steel and one enamel that are useful for reconstituting rice, and the stainless steel one serves as an extra saucepan on occasion. We have a spoon each and a sharp knife.
Last trip we also took a small coffee plunger, which was grossly over the top, but well worth every extra ounce. Mmmmmmm. Real coffee. It survived the trip but succumbed to Air New Zealand cargo handling practices on the way home despite being well insulated inside the pack. Fortunately broken glass remained inside the initial container, and did not make its way into other gear.
We use the standard squat canisters containing about 227g (8 oz) of gas. Typically the Kovea stove uses 20 g of gas to raise 1 litre of water to boiling point. I'd probably take 2 canisters for a trip up to 4 days, and 4 canisters for a week away, assuming we intend to be using two stoves during dinner prep.
Incidental Travel Tips Concerning Equipment
You may not take gas canisters or matches or gas lighters on planes. If you're flying to the start of the track, ie from the North to the South Island, buy your canisters immediately before you start tramping, and leave unfinished canisters in the last hut with a "free for removal" note.
Make sure that any knives or other sharps are safely packed in luggage you know will go in the hold of the plane.
On my way south to do the St James Walkway, my day pack, containing a sharp vegetable knife was handed back to me at Auckland check-in as cabin baggage and on my way through the X-Ray machine I was motioned aside and was forced to watch as a customs officer unpacked e-v-e-r-y item in the pack to establish that I was not about to terrorise anyone.
I was so upset I even forgot to get a photo record of the process.
Being an inquisitive kind of guy he also wanted to know about the unlabelled plastic bag containing the white crystalline substance. I tried to explain about Horley's "Replace" but it's very difficult when you've discarded the original container, and the guy you're talking to hasn't got a clue about electrolytes, apart from the one he switches off before he goes to bed. I suggested he get a dog to have a sniff at it, but they were all down at the overseas terminal.
It took me for ever to repack my daypack. It had taken real planning to fit everything in to start with. Miranda was very patient and if she was thinking plenty, she said absolutely nothing.
So DO be careful not to attract official attention.
I also had to buy another sharp knife in Christchurch. It survived the trip home, even if the coffee plunger didn't make it.
Post script. On the way home, our original flight was cancelled for one reason or another and a thoughtful Air New Zealand official had booked a group of us onto some empty seats on an international flight just in from Australia and on its way to Auckland. Just as we were getting ready to board, he remarked, "I don't suppose anybody's got any food in their luggage as you'll all be going through the international customs check at Auckland."
JEE-ZUZ. There was left over tramping food in just about every bag we had.
I recalled that a friend of ours has been done $200 instant fine for an Australian apricot in her hand bag that she'd completely forgotten about. I waved both arms and started to make loud agitated noises.
"No, sir, there's no way we can separate out the Christchurch passengers from the international passengers. You'll all have to go through international customs."
I pointed out that none of us locals was likely to be carrying passports with us, for a start, but to no avail. There was obviously a strong suspicion that in the next hour a conspiracy to smuggle apricots would likely be hatched between ourselves and the passengers from Sydney. (If that wasn't enough there was also in our luggage a jar of Barker's Apricot sauce we had purchased in Geraldine.)
The plane was due to take off in about ten minutes. I indicated to the official that it would take me at least half an hour to disgorge every last crumb of food from our baggage and he would have to get the cargo bags back as well as they were also involved, and I was in a good mind to sue for the replacement value of every last bit of discarded mince and instant mashed potato, having invited absolutely none of this nonsense.
He conceded eventually that I might have a point and we were ushered into a separate area, followed by several others who recognised they were in more or less the same situation. He disappeared, and emerged shortly looking flustered but triumphant. We were pointed at another flight leaving immediately, and bound for Auckland domestic terminal, along with our luggage. It could have been much worse......