The Drugs Act specifically deals with drugs it names as ‘drugs of dependence’ dealt with under Part V of the Act. Schedule 11 contains a list of drugs and their quantities, possession of which would constitute an offence under the Act. This includes drugs (street names used) steroids, marijuana, heroin, MDMA, GHB, ecstasy, cocaine, acid etc. For a full list please refer to Schedule 11. It is to be noted that if a person possesses a certain quantity of drugs, that is prima facie evidence that that person was trafficking in that drug. This can mean that if a private user of drugs has a large amount of that drug on them, they are assumed to be trafficking in that drug and can receive a heftier punishment. For example, a man with 3.3 grams of cocaine may be deemed to be trafficking – regardless if it was for personal consumption.This then places the onus on the accused to demonstrate it was for personal use.
If you have been charged with possessing, manufacturing, trafficking or selling drugs of dependence it is imperative that you contact a lawyer as soon as possible.
Knowledge and possession
Knowingly possessing these drugs is contrary to these Acts and is therefore illegal. It is up to the prosecution to prove that the accused knew of the drugs in question. For example, Sweet v Parsley  AC 132 involved a woman who leased a house in London. When she visited Oxford she sub-let the rooms, and kept one for herself. While she was in Oxford drugs were found at the house and she was convicted by a magistrate of being involved in management of premises that was used for smoking cannabis. She appealed all the way to the House of Lords. They held that as she had no knowledge of the drugs, she therefore had no crime of it.
Up until 2010, Victoria had operation of what was colloquially known as ‘deeming provisions’ found in s.5 of the Drugs Act. This essentially meant that substances found in a person’s house were deemed to be in their possession, unless the accused could satisfy on the balance of probabilities that these substances did not belong to them. This is what essentially occurred in the case of R v Momcilovic  VSCA 50. She subsequently challenged these provisions under the Charter of Human Rights and Responsibilities Act 2006.
Specifically s.25(1), which is the requirement that all legislation be compliant with the right to a presumption of innocence. Also if the quantity of the drugs is so minute, that will affect the knowledge requirement for the offence to be complete. See Williams v R  HCA 49
The High Court allowed an appeal where the applicant stated that due to the minute amount of the drugs he did not know that he possessed it. For example, a man that had a tiny amount of cocaine that can only be detected by scientific means cannot be deemed to have knowledgeably possessed that drug.
Furthermore if an accused knew he was importing something (even if it was illegal itself) but did not know it was drugs, then the knowledge requirement is not satisfied. See R v Taafe  VSCA 4:
FACTS: A man was believed he was smuggling currency but was actually smuggling drugs.
HELD: Even though he was smuggling illegal currency, he did not have the requisite guilty mind for the offence to be satisfied.
It is to be noted that this is distinguished from where an accused has a guilty mind that he is importing drugs, but the drugs turn out to be a different type of drug.
The requirement for possession is defined in s.73 of the Drugs Act. Possession of a thing in criminal law involves physical control or custody of that thing plus the knowledge that it is in possession (see He Kaw Teh v The Queen  HCA 43). The physical control of that thing can be shared, but must be exclusive possession to all other persons (apart from the people who are sharing it) (see R v Filipetti). The case of Filipetti held that finding drugs in a lounge room of a house with six people living in it, where all six had access, did not satisfy the requirement of exclusive possession. See also the case of Mogilevsky v R  NSWCCA 92 for more information.
Please note that this area of law can turn drastically on the facts and can become extremely complex. If you have been charged with drug offences it is highly recommended that you contact a competent lawyer. Grigor Lawyers can can advise and represent you in these matters.