Phat, NZ has no native mammals. Once you are above the sheep stations, the likelihood of drinking contaminated water is just about zero. The challenge there is weather. I've seen it go from a warm sunny day to a major storm in a few hours. Anyone who goes out unprepared for bad weather is asking for trouble.

As for the idea that you have to take risks to gain experience, I don't buy it. Depends on your definition of risk, I suppose, but there is much you can learn with little or no risk at all. I don't think I've taken any risks on my solo winter trips and yet I think I have learned a fair amount about winter camping on those trips.