For short term Visas

People from some countries don't need a visa to enter New Zealand. However, they are still required to provide:
 

• travel tickets or evidence of onward travel arrangements, and

• evidence of funds for maintenance 

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.

List of visa free countries

Andorra

Argentina

Austria

Bahrain

Belgium

Brazil

Brunei

Bulgaria

Canada

Chile

Cyprus

Czech Republic

Denmark

Estonia¹

Finland

France

Germany

Greece⁵

Hong Kong²

Hungary

Iceland

Ireland

Israel

Italy

Japan

Korea (South)

Kuwait

Latvia¹

Liechtenstein

Lithuania¹

Luxembourg

Malaysia

Malta

Mexico

Monaco

Netherlands

Norway

Oman

Poland

Portugal³

Qatar

Romania

San Marino

Saudi Arabia

Singapore

Slovak Republic

Slovenia

South Africa

Spain

Sweden

Switzerland

United Arab Emirates

United States of America⁴

Uruguay

Vatican City

¹Visa waiver does not apply to people travelling on alien's (non-citizen's) passports issued by these countries.
²Residents of Hong Kong travelling on Hong Kong Special Administrative Region or British National (Overseas) passports.
³Portuguese passport holders must also have the right to live permanently in Portugal.
⁴Including nationals of the USA.
⁵Greek 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.)
 

Source: http://glossary.immigration.govt.nz/visafreecountries.htm