I took out NZD 800 in cash for three weeks - two of which I spent touring the South Island. In the end, I struggled to spend the cash. I gave 250 to a friend, and paid several things cash on the final three days. Still, I left with some cash in hand.

I encountered few places that would not take credit cards (one of them was a yummy Chinese restaurant in Highbury in Auckland), and I don't remember any declined transactions.