During the fligh, on the plane prior to arrival, will be delivered a paper to fill so you better have a pen in your bag . This document is divided into two parts, one about you and the second for customs. The form has no mystery, and it is just fill the passport number, your name, how long will stay in the country, the reason for travel (tourism, business, study, etc.) and other questions. NZ Customs  asks a lot of things, such as if you were recently on a farm, if you are bringing food, if there are seeds or forbidden material such as porno stuff and so on. There is a line column to say yes or no, and they will check later, in case you did not report you have food and they found it in your luggage- so you may get a fine. 

Well, New Zealand is an insular country and the nearest neighbour is more than 2000 kms. It has no diseases and pests in crops as many other countries may have. So anything brought from outside may cause a collapse in the economy, if a plague spreads across the country. New Zealand set very high fines if you fail to declare a food, seeds and certain objects made with straw, some types of wood, as well as clothes or ornaments, made ​​with certain types of animals parts such as ivory, skins, etc. The list is long, and it is difficult to know exactly what is allowed or not but they have a list informing people about it. Fresh food such dairy or milk products like cheese, meat, ham, fruits, and everything that comes from a living being can not enter. Not even the food served in the plane. More informtion look at  Quarantine NZ..

Real Case: In May 2005, in front of me, a Chinese woman was fined to pay in the act NZ $ 2,500, and the Customer officer was benevolent, I heard about a Filipino man got NZ 35,000 fine (the maximum isNZ$ 50,000) . So if by any chance you are bringing any food or anything else that you are not sure if it is allowed, go for the RED section and show the stuff you have to Customes and they will decide about it. If it's ok you will get your stuff  returned or if not they will put in a garbage bin. So Do not hesitate, they have sophisticated machines that see through suitcases. Beware of the snacks your mother put in your backpack without warning, in doubt, do not hesitate, enter the red sector. 

Drugs even milder one such as marijuana is prohibited in New Zealand, and be aware that at the airport they have high trained dogs for drugs and explosives. If caught with drugs they may give you a fine and even deportation. If you take some kind of medicin sold by prescription only, bring the prescription with you and the packaging where the ingredients are listed and stay calm. The office does not usually mean much at this point, but there are drugs that are banned in NZ, and are not in other countries. Bring the prescription in case you are bringing some stock to suply you for a long time, because to buy any remedy in NZ, you will need to consult a doctor. You medical history translated into English will be very helpfull in this case.

There is no rule to limit the amount of money to bring to New Zealand, but any thing above NZ $ 10 000 must be declared in the form they wiill distribut. There is no problem to say you have such amount of money with you. But if you hide the fact and be caught you will have to pay a fine as well justified the reason.

To party inside the plane may even result in your visa be refused, because the flight attendant will inform the captain, who will be communicating to the tower, which links to immigration. Some people may abuse of the free drinks on board, and think they can make a private party in the air. These already happened a few times, and it is clear that these people will face a hard time at the customes and even compromise other people from the same nationality, as you may be  punish by the mistakes and lack of education from your mates.

  The allowence limit of non taxable things at customs in NZ ( duty free) is NZ $ 700 (your laptop or camera is not included), purchased for your own use or for a gift. Make sure you have receipts available for inspection. If you plan to take in anything beyond those limits, contact the embassy or consulate office nearest you before you arrive or check www.customs.govt.nz. The limit  for tabaco is 200 cigarettes or a carton package per person. Alcoholic beverages is up to six bottles (4.5 litres) of wine, port or sherry, up to twelve cans (4.5 litres) of beer. Three bottles (or other containers) each containing not more than 1125ml of spirits, liqueur, or other spirituous beverages. Quantities imported in excess of the allowances,are liable for Customs charges.but you will pay tax only on the value exceeding. 

Do not accept to watch anyone's suitcase or backpack at the airport, and do not let your stuff with someone you do not know the person well. For example an Australian got 15 years in jail in Bali for marijuana stuffed inside the cover of her bodyboard. Do not leave your bag or backpack hanging around alone at the airport. Because of global terrorism, it can even be exploded by the police with all your things inside.

Once you have received the visa to  stay or work in New Zealand, and intend to stay longer, do not forget to renew your visa before it expires .

Even food from the plane is not allowed to enter New Zealand.