Currency is New Zealand dollar.
Bills, made with polymer (plasticised) as in Australia, are divided in 100, 50, 20, 10 and 5N$.
There are five different coins: 10, 20, 50, 1 and 2Z$.
Credit card is the best way of payment. Visa and MasterCard are accepted everywhere, in contrast to American Express or Diner Club. They also take out an insurance that covers you during your stay, including sometimes rental cars.
The biggest New Zealand banks, ANZ, ASB, Bank of New Zealand, National Bank of New Zealand, have branches everywhere in the country, with DAB (ATM) usable 24/24h.