Hi Chuck, not sure that NZ wool is any better than other wool, but as the place is full of them it is very easy to pick up an untreated tuft of wool from the nearest farm fence, the lanolin makes it float, but it will still sink after a while! The main thing is that finding untreated wool in other places may be a bit harder. Mostly I leave the sheeps wool to the sheep and just use a pinch on indicator or a dry fly.
All the best.
Mike