Ecstasy users should not be charged by police, former federal health minister Neal Blewett says.

The former Labor MP also says cannabis laws around the country are "chaotic" and need reform.

Dr Blewett made his assertions in a keynote address to a police drug and alcohol forum in Australasia on Tuesday.

He believed resources should target the most serious drug abusers.

"Already we struggle with drugs, including designer drugs scarcely on our horizon in the past," said Dr Blewett, the minister who launched Medicare.