Supply reduction

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Legal substances Medicinal substances Prohibited substances Drug seizures Wastewater analysis References

Supply reduction involves ‘preventing, stopping, disrupting or otherwise reducing the production and supply of illegal drugs; and controlling, managing and/or regulating the availability of legal drugs’ (Department of Health 2017b).

Information on the availability of alcohol, tobacco and other drugs in Australia comes from research with people who use drugs, seizure data from law enforcement agencies, wastewater analysis and information collated from international sources in relation to drug manufacturing and importation.

Legal substances

The consumption of alcohol and tobacco by adults is legal in Australia. Almost 1 in 2 (46%) Australians aged 14 years and over approved of regular adult consumption of alcohol compared with 15.5% who approved of regular tobacco use (AIHW 2024).  Alcohol and tobacco products are available for purchase; however, there are a number of strict regulations that control their supply. Specific supply reduction interventions include:

  • controls prohibiting or restricting drugs at the border (such as illicit tobacco or nicotine e-cigarettes that are not supplied with a prescription)
  • the enforcement of a minimum purchasing age
  • restriction of operating hours for venues supplying alcohol
  • restrictions on the size and strength of beverages or the number of drinks that can be purchased at one time, and the size (minimum number of cigarettes) of cigarette packets.

Medicinal substances

Controls governing the marketing and availability of pharmaceutical drugs for the treatment of illness or injury is determined based on an assessment of evidence of their risks and comparing that to the evidence associated with their benefits. This means that certain higher risk pharmaceutical drugs may only be lawfully supplied on prescription from a registered health practitioner, while others are more widely available and accessible (TGA 2022). Generally, certain controls also apply in relation to the quantity of the drug supplied and directions for consumption, including the provision of advice to the consumer on restricting the use of these drugs in combination with alcohol and other licit and illicit drugs (TGA 2018).

When pharmaceutical drugs are used for non-medical purposes, the drugs can be diverted or channelled from the legal supply system to the illegal marketplace for misuse. This process of diversion may occur in a number of ways such as sharing between family and friends, theft, prescription forgery, doctor shopping, illegal sale and over prescribing by health practitioners. Policies aimed at reducing the supply of pharmaceutical drugs for non-medical use in Australia, include:

  • border controls limiting the entry of nicotine containing e-cigarettes and e-liquids that are not supplied with a prescription or other appropriate exemption
  • agreement to develop a national real-time prescription monitoring system
  • the up-scheduling of codeine (1 February 2018) to a prescription-only medication
  • the up-scheduling of alprazolam (1 February 2014) from prescription-only to a controlled medication.

In 2016, cannabis became available medicinally in Australia for specific patient groups under strict medical supervision. Other than in these limited circumstances, the cultivation, possession and supply of cannabis remains prohibited in Australia (Department of Health 2017a).

Prohibited substances

The possession and supply of other illicit drugs such as cannabis, meth/amphetamine, heroin and cocaine are prohibited in Australia. Illicit drugs are commonly sourced for use from friends and relatives, dealers and online (AIHW 2024). Research with people who use drugs suggest illicit drugs are readily available in Australia.

The Illicit Drug Reporting System (IDRS) is an annual survey of people (18 years and older) who injected drugs at least once monthly in the preceding 6 months and resided in the capital cities of Australia; it includes questions about the availability of illicit drugs. The latest IDRS data were collected from June–July 2023.

In 2023, most IDRS respondents indicated that cannabis, crystal methamphetamine, cocaine and heroin were ‘easy’ or ‘very easy’ to obtain:

  • Over 9 in 10 (94%) respondents reported that crystal methamphetamine was ‘easy’ or ‘very easy’ to obtain, an increase from 91% in 2022.
  • Over half (56%) of respondents perceived heroin to be ‘very easy’ to obtain, an increase from 2022 (43%) (Sutherland et al. 2023b).

The Ecstasy and Related Drugs Reporting System (EDRS) is an annual survey of people who regularly use ecstasy and other stimulants and includes questions on the availability of illicit drugs. The latest EDRS data were collected from April–July 2023.

In 2023, most EDRS respondents indicated that methamphetamine, cocaine, and cannabis and/or cannabinoid related products were ‘easy’ or ‘very easy’ to obtain. Large changes were observed in the perceived availability of ecstasy pills relative to 2022. Additionally:

  • Nearly 1 in 3 (30%) people reported ecstasy pills to be ‘difficult’ to obtain, a decrease from 39% in 2022.
  • 2 in 3 (68%) people perceived crystal methamphetamine to be ‘very easy’ to obtain, up from 62% in 2022.
  • Nearly 2 in 5 (37%) people perceived cocaine to be ‘very easy’ to obtain, an increase from 34% in 2022.
  • 3 in 4 (73%) people perceived hydroponic cannabis to be ‘very easy’ to obtain, up from 64% in 2022 (Sutherland et al. 2023a).

Changes due to the impacts of COVID-19 resulted in EDRS and IDRS interviews in 2020-2023 being delivered face-to-face as well as via telephone and videoconference. All interviews prior to 2020 were delivered face-to-face, this change in methodology should be considered when comparing data from the 2020–2023 samples relative to previous years. 

Box HARM1: Data sources of regular drug consumers

The National Drug and Alcohol Research Centre (NDARC) Drug Trends program monitors trends in drugs across Australia. Information is collected from a range of sources including annual interviews with people across Australia who regularly inject drugs through the Illicit Drug Reporting System (IDRS) and those who regularly use ecstasy or other stimulants through the Ecstasy and Related Drugs Reporting System (EDRS). The IDRS and EDRS sample is a sentinel group that provides information on patterns of drug use and market trends.

The IDRS consists of annual interviews with people who regularly inject drugs, participants are recruited from all  capital cities of Australia. The monitoring system is intended to provide trends and identify emerging issues in illicit drug markets (Sutherland et al. 2023b).

The EDRS uses a similar methodology to the IDRS in that it uses annual interviews with people who regularly use ecstasy and other stimulants. The EDRS monitors the price, purity and availability of ‘ecstasy’ and other drugs such as methamphetamine, cocaine, gamma-hydroxybutyrate (GHB), d-lysergic acid (LSD), 3,4-methylendioxyamphetamine (MDA) and ketamine. It also examines trends in the use and harms of these drugs (Sutherland et al. 2023b).

It is important to note that the results from the IDRS and EDRS surveys are not representative of people who use illicit drugs or the general population. The aim of these data are intended to provide evidence that is indicative of emerging issues that warrant further monitoring.

Further information about the Drug Trends program.

There have been fluctuations in the illicit drug market at certain times. For example, in the early 2000s there was a widespread heroin shortage in Australia, which followed a period of unprecedented heroin availability in Australia in the late 1990s. The heroin shortage has been attributed to a range of factors, including high purity and low profit margins for dealers, along with a number of law enforcement seizures (Degenhardt, Day & Hall 2004).

Examples of supply reduction initiatives to limit the availability of illicit drugs include:

  • law enforcement operations involving drug seizures and arrests
  • disrupting the diversion of precursor chemicals that are used in the manufacture of illicit drugs.

Drug seizures

The Australian Criminal Intelligence Commission (ACIC) collects national illicit drug seizure data annually from federal, state and territory police services, including the number and weight of seizures to inform the Illicit Drug Data Report (IDDR). According to the 2020–21 IDDR there were:

  • 105,694 national illicit drug seizures, equivalent to around one seizure every 5 minutes. 
  • There has been an increase in the number of seizures over the last decade from 76,083 in 2011–12.
  • There has been a 13% decrease compared with the previous year (Figure HARM3). 
  • Cannabis (52%) and amphetamine-type stimulants (ATS; 27%) accounted for the greatest proportion of national illicit drug seizures in 2020–21.
  • The number of cannabis seizures decreased 12% in 2020–21 and ATS seizures decreased 27% compared with 2019–20 (ACIC 2023).

The weight of illicit drugs seized nationally was 41.4 tonnes in 2020–21, an increase from 38.5 tonnes in 2019–20 (8%). Additionally:

  • The weight of illicit drugs seized in 2020–21 increased from the previous year across all drug types except ATS, which decreased by 51%.
  • Illicit drugs classified as other and unknown accounted for the greatest proportion of the weight of illicit drugs seized in 2020–21 (45%) followed by cannabis (26%), ATS (15%), cocaine (11%) and heroin (3%). 
  • There has been a 74% increase in the weight of illicit drugs seized over the last decade (23.8 tonnes in 2011–12) (Figure HARM3). 

Figure HARM3: Number or weight of national illicit drug seizures, by drug type, 2011–12 to 2020–21

This figure shows that the number of seizures has increased from 2011–12 to 2020–221. In 2020–21, most seizures were for cannabis (55,199 seizures) and amphetamine-type stimulants (28,503 seizures).

View data tables >

Wastewater analysis

Wastewater analysis provides estimates of drug usage in a population by measuring concentrations of drug metabolites (excreted into the sewer system after consumption) in wastewater samples. The National Wastewater Drug Monitoring Program (NWDMP) of the Australian Criminal Intelligence Commission (ACIC) monitors selected substances of concern in most populated regions of Australia (ACIC 2024).

Sixty-two wastewater treatment sites participated nationally in the August 2023 collection (Report 21 of the NWDMP), with 22 sites located in capital cities and 40 in regional locations. This covers around 57% of the Australian population, or about 14.5 million people. 

Of the available dose data, alcohol and nicotine remain the highest consumed substances. Cannabis was the most consumed illicit drug, followed by methylamphetamine (ACIC 2024).

Box HARM2: Differences between self-reported illicit drug consumption data and wastewater analysis data

It is important to note the different methodologies and sample coverage for self-reported illicit drug consumption data, such as the National Drug Strategy Household Survey (NDSHS), and wastewater data analysis. The National Drug Strategy Household Survey (NDSHS) findings are based on self-reported survey data from people aged 14 and over who live in residential dwellings; this excludes people living in non-private dwellings, institutions (such as prisons and drug and alcohol rehabilitation centres) and people experiencing homelessness. Results, indicative from all over Australia, are not verified by blood tests or other screening measures and estimates of illicit drug use in the NDSHS are likely to be underestimates of actual use. In addition, some non-response bias is expected, but this bias has not been measured. The National Wastewater Drug Monitoring Program (NWDMP) measures the level of consumption of the specified substances within the community and covers just over half of the population.

For further information, see:

The ACIC has assessed the relationship between supply and demand in the Australian methylamphetamine market by overlaying data from the NWDMP with illicit drug seizure data. The key findings indicate that large seizures have an impact on consumption, particularly in capital cities. The impact is not immediate and usually lasts between 2 to 4 months (ACIC 2019).

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