Perth drug use rivals Kings Cross

Almost half those arrested over crimes in central Perth this year have taken amphetamines, a result second only to Sydney's Kings Cross.

The Australian Institute of Criminology said 43 per cent of detainees at Perth's main lockup tested positive to amphetamine, compared with 61 per cent of inmates at Kings Cross and 39 per cent nationally.

But more offenders at Perth actually returned positive tests, because 159 of them provided urine samples, while just 18 did in Kings Cross.

The results from the first three months of the year, based on voluntary surveys and tests of Australian police detainees, reflected the high availability and steady rise in amphetamine use, the institute said.

Research manager Matthew Willis said the latest positive amphetamine test results at WA's main lockup was a "significant increase" after rates had stayed between 27 per cent and 37 per cent from late 2011 to the end of last year.

He said given that amphetamine use, in particular methamphetamine use, was associated with an increased risk of violence and aggression, a rise in use among Australian detainees was concerning.

Professor Steve Allsop said police, paramedics and hospital staff could find people high on amphetamines, especially those also affected by alcohol, hard to manage.

The National Drug Research Institute director said users could be more aggressive but were also likely to be paranoid, agitated or highly distressed.

Though it was difficult to determine the exact rates of amphetamine use, surveys such as these indicated recent increases, Professor Allsop said. But he did not think amphetamine use had reached the levels of the early 2000s.

Of the 159 Perth detainees who have provided samples, 33 per cent had more than one drug in their system.