Spiralling living costs have had little impact on illicit drug use as Australians consume record amounts of ketamine and other banned substances.
The latest wastewater monitoring report showed use of both methamphetamine and cocaine had reached the highest levels in three years, based on data from April and June 2023.
The Australian Criminal Intelligence Commission said Australians were relatively high per-capita users of illicit stimulants in particular and were willing to pay premium prices for drugs.
The data was collected in all states and territories, covering more than half of the population.
While the average consumption of heroin, MDMA and fentanyl had decreased compared to the last report, there were increases in alcohol and oxycodone use.
Methamphetamine and cocaine consumption increased to the highest levels recorded since 2020.
In April 2023, the data showed record-high ketamine use in cities and the regions, with higher consumption in capitals than in regional areas.
In cities, per-person methamphetamine, cocaine, MDMA, heroin and ketamine use exceeded that of regional areas.
But in the regions, alcohol, nicotine, oxycodone, fentanyl and cannabis consumption exceeded per-capita use in capital cities.
The commission's report is compiled as part of law enforcement efforts to target drug supply and demand, and reduce harm.
Acting chief executive Matt Rippon said the data underlined the pervasive and ongoing threat posed by organised crime groups in Australia to gain large profits at the expense of the community.
"Drug consumption estimates derived from wastewater data - when used in combination with other data such as seizure, arrest, price, purity, health and availability data - provide the most comprehensive, empirically-based insights into Australian drug markets," he said.
"In turn, these data reveal drug market resilience, but also points of vulnerability that present opportunities to inform harm reduction strategies that improve the safety of the Australian community."
Excluding nicotine and alcohol, the data showed cannabis was the most consumed drug by a large margin.
Cannabis use has increased in capital cities but decreased in regional areas.
In the latest reporting period, MDMA consumption continued an ongoing trend of a decline in consumption since December 2019.
Heroin consumption decreased in both capital city and regional areas to a combined level that was the fourth lowest since the wastewater program began in 2017.
Oxycodone consumption increased in both capital city and regional areas, while fentanyl consumption decreased in both.
