Cannabis is the most widely used illegal drug in New Zealand . In the population of more than 4-million, 13.4% of those between the ages of 16–64 use cannabis . This ranks as the ninth highest cannabis consumption level in the world. [1] The use of cannabis in New Zealand is governed by the Misuse of Drugs Act 1975 , which makes unauthorised possession of any amount of cannabis illegal. However, there are some political efforts seeking to remove penalties on its use for those over 18 years of age.