Cannabis use is controlled by the Misuse of Drugs Act 1975. Possession of any amount of cannabis is illegal. The maximum penalty for possession of cannabis is imprisonment for a term not exceeding 3 months or a $500 fine, although section 7(2) of the Misuse of Drugs Act 1975 contains a rebuttable presumption against imprisonment in respect of possession offences in respect of Class C controlled drugs, which include cannabis. Cultivation of cannabis carries a maximum penalty of 7 years imprisonment. Selling cannabis, offering to sell or supplying cannabis to a person under the age of 18 years carries a maximum penalty of 8 years imprisonment. Cannabis oil or hashish are defined as a class B drugs, and those convicted of manufacturing or supplying face a maximum penalty of 14 years imprisonment. Possession of a class B controlled drugs carries a maximum sentence of up to 3 months imprisonment or a fine not exceeding $500.
Anyone caught in possession of at least 28 grams of cannabis or 100 cannabis joints is presumed to be a supplier, unless the defendant can prove they are not. However, in R v Hansen, a majority of the Supreme Court held that this presumption was inconsistent with section 25(c) of the Bill of Rights Act, which affirms the right of those charged with an offence to be presumed innocent until proven guilty. They also held that it was not a justified limitation under section 5 of that Act. Cannabis is a Class C drug, of which the penalty for dealing can result in a maximum prison sentence of 8 years under the Act. There have been many public campaigns to decriminalise Cannabis but so far none have succeeded. It is generally accepted that the usage rate is high and possession in small quantities may not often be prosecuted. In some cases first offences may result in a formal warning and confiscation by police.