While import and export of currency is allowed and unused dollars can be changed into foreign currency on departure, sums above NZ$ 10,000 will need to be declared on entry or departure by filling up the Border Cash Report.
How much money you spend in NZ depends on how much you want to live it up. Staying at motels and hotels can be more expensive. But if you want to stay in hostels and motor camps then the cost will come down to a reasonable sum. There are so many campsites, B&Bs, guesthouses, hotels and motels of all ranges that you can always find something to suit your budget.
Travelling usually accounts for the biggest chunk of expenses, especially in a country where you need to fly to cover more than one part. Though NZ appears compact, set aside enough reserves to cover travelling expenses.
To cut down on travelling costs, renting a car is a good option if there's a group of 4-5 people. Just make sure one of you has a valid drivers license. Sightseeing and outdoor activities, some of which may be free, can take up a lot of your budget since the scope is so immense.
The best way to carry money is in the form of Travellers Cheques, which have lower exchange rates than cash. Credit Cards are useful for car rentals and hotels, as long as you don't have to pay an outrageous sum of money to use them in NZ. Getting an ATM card issued by your bank for your trip is a nice idea.
If you intend to stay a long time then opening a bank account with an ATM service is a good idea. ATMs & Credit Cards - Standard credit cards are commonly used and honoured in NZ. For cash you'll need to head to their offices in the main cities. ATM facilities may be available for oversees savings accounts so check with your bank before going and get a pin number.
Exchange money at Banks, Hotels and Bureau de Exchange kiosks at the international airports or in the city centres. Money can be changed at banks that are open daily from 9 a.m. to 4.30 p.m., some are open on Saturdays, and others even on Sundays.