New Zealand Travel Guide
Tipping is not as widely practiced in New Zealand as in the United States or Europe, but in city restaurants and hotels it's appreciated if you acknowledge good service with a 10% tip. Tour guides and drivers would also be used to receiving some gesture, even though it isn’t mandatory.
Taxi drivers will appreciate rounding up the fare to the nearest NZ$5 amount, but don't feel you have to do this. Porters will be happy with a NZ$1 or NZ$2 coin. Most other people, like bartenders, theater attendants, gas-station attendants, or barbers, will probably wonder what you are doing if you try to give them a tip. The nice thing about this is good service in New Zealand is given because the person means it, not because they’re aiming for a good tip.