Amphetamines easy to find: study

Police might be notching up record methamphetamine busts but it doesn't seem to be denting supply for many drug users.

A study has found that a significant number of Australian users have never experienced any shortage of the drug.

Those who found it hard to get for a while simply reduced their intake or abstained, without increasing their use of alcohol or other drugs.

In the study, Australian Institute of Criminology researchers interviewed 550 detainees in police lockups in Perth, Brisbane, Adelaide and Sydney during the third quarter of 2013 as part of the long-running Drug Use Monitoring in Australia program.

They found 47 per cent reported using methamphetamine in the previous year.

This high usage rate was confirmed by urine testing - a third of the 375 who supplied a urine sample tested positive.

That's a 10 per cent increase in less than a year, and a 21 per cent increase on a similar study in 2009.

Detainees who admitted they were regular users were asked about the last time methamphetamine was hard to get.

More than half (109) said they had never experienced a shortage.

"This indicates that methamphetamine has remained readily available across Australia, despite an increased number of seizures by law enforcement," the study says.

Because amphetamines are both imported and produced in Australia, it's not clear whether law enforcement efforts could produce a substantial shortage as occurred suddenly with heroin in 2000-01, the study said.

However, there was some evidence that policing was hitting supply with record amphetamine seizures last year.