If you wish to come to New Zealand to study full-time for more than 3 months, you will need a student visa. The visa allows you to enter a country and allows you to stay in the country based on the terms & conditions given in your visa. When you enter the country the visa or custom officer at the airport will check to confirm & validate your visa and passport is also valid. They will then issue or stamp your passport with a permit. You must have a valid permit at all times while you are in that country.
Permits can be renewed and converted at the Immigration Service Office on completion of the application requirements. Each student visa and student permit will specify the course of study, the school or institution and its specific location.
In some countries Visa itself is a permit. You will need a student visa if you wish to come to New Zealand to study full-time for more than 3 months. You can only get a student visa to study in an option at an education institution, which is registered and authorized by the New Zealand Qualifications Authority. Student Visa applications are been processed by New Zealand Immigration Service through Gateway Immigration.
Your student visa will be issued for the span of time till your course tuition fees have been paid. If you are studying a long-term course at a secondary school, University or Polytechnic you will normally pay your tuition fees every year. Visa application should be lodged for at least 2 months preceding to the course commencement date.