If the course you want to study is a single short course of less than three calendar months duration,  if students from some countries don't need a student visa to enter New Zealand for . However, they are still required to provide:

travel tickets or evidence of onward travel arrangements, and evidence of funds for maintenance.

If you are visiting for three months or less and are from a country in the list below, you will not need a visa.
 

* Visa waiver does not apply to people travelling on alien's (non-citizen's) passports issued by these countries.

** Residents of Hong Kong travelling on Hong Kong Special Administrative Region or British National (Overseas) passports.

*** Portuguese passport holders must also have the right to live permanently in Portugal.

**** Including nationals of the USA.

***** Greek passport holders whose passports were issued on and after 1 January 2006. (Greek passports issued before 1 January 2006 are not acceptable for travel after 1 January 2007).

United Kingdom and Australia
British citizens and other British passport holders who produce evidence of the right to reside permanently in the UK can visit for up to six months without a visa.

Australian citizens and people who hold a current Australian permanent residence visa or a current Australian resident return visa do not need a New Zealand visa to enter New Zealand.

More update information about New Zealand Visa and Permit, please visit the official New Zealand Immigration web site http://www.immigration.govt.nz

For student who is not  from Visa Free Countries, you need check if you are Positive  Profile students before applying for student visa. For more information, please visit local Licensed New Zealand Immigration Adviser website: Asky International Ltd