A new study shows Australia and New Zealand have the highest proportion of cannabis and amphetamine use in the world.

The figures published by medical journal The Lancet show marijuana use in Australia is three times the global average, with amphetamine usage twice as common.

The journal has published a series of papers measuring the scale of drug use around the globe and assessing the way governments are dealing with the issue.

The major study - led by Australian researchers - shows cannabis remains by far the most commonly used illicit drug around the world.

Professor Louisa Degenhardt, from the National Drug and Alcohol Centre, says Australia's drug use patterns are quite typical.

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"Use patterns in Australia are pretty typical of many high-income countries," she said.

"Cannabis is the most widely used drug by far; amphetamine use is more common than cocaine, although we have seen an increase in cocaine use in recent years.

"Opioid use remains the most common cause of illicit drug-related deaths in this country, although in 2012 levels of abuse are lower than they were in the 1990s."

Professor Degenhart says a much smaller proportion of Australians use heroin than other drugs but the health consequences are far more serious.

The research shows up to 21 million people worldwide use opiates like heroin, which accounts for 80 per cent of drug-related health problems.

Professor Wayne Hall, from the University of Queensland's Centre for Clinical Research, says users of opioids have a higher dependency.

"They are major contributors to premature death in young adults from fatal overdose, accidents, suicides and violence, and when people inject them as they often do with drugs like heroin, blood-borne virus infections such as HIV/AIDS and hepatitis C," he said.

Cannabis dangers

Figures from 2009 show up to 15 per cent of Australians aged 15 to 64 used cannabis in that one year, but the health impacts are significantly less than heroin.

"[It] causes very few deaths; it's difficult if not impossible to overdose on the drug," Professor Degenhardt said.

"It cannot be injected so it is not a risk for blood-borne viral infections, but it can cause morbidity, particularly in terms of becoming dependent on the drug.

"[It] probably contributes to the development of mental disorders and if used regularly in adolescence, contributing to poor psycho-social adjustment during that time."

Amphetamine use in Australia is rising and its health consequences are much more severe than cannabis.

"Amphetamine use is more common than cocaine, though we have seen some increases in cocaine use in recent years," Professor Hall said.

One of the aims of the research was to assess the way governments deal with the drug problem.

Professor Degenhardt is critical of the impact of the illegal status of drugs.

"We see increased criminal activity in order to fund drug use among problematic users," she said.

"There may be increased risky behaviour among users who are worried about being detected by police and either not being able to take their drugs or being arrested.

"Because of the stigma and discrimination, it just discourages treatment seeking particularly in some countries where treatment is likely to be highly stigmatising or involve incredibly coercive measures."