A visa gives you permission to travel to New Zealand. It will list the conditions under which you're able to enter New Zealand and obtain a permit.
Once you arrive, for example at a New Zealand airport, an immigration officer will check your visa. If the officer is happy you meet all the conditions stated on the visa, they'll grant you a permit. It is the permit that gives you permission to be in New Zealand and states the date your permit will expire and any other conditions that apply.
The permit is stored electronically on your personalised webpage and available to you online at our Online Services. The Visa label in your passport contains the same information as the electronic permit.
A single entry visa allows you entry for the one journey only. Your permit expires when you leave New Zealand. However, if you hold a multiple entry permit and you have not been here for the full length of the time your permit allows, you'll be able to re-enter New Zealand on your return and remain here for the balance of your permit.