An urgent search is underway for a man police believe will be able to assist in a current investigation.

The public is urged to not approach 54-year-old Alan John Slater, who is known to frequent the Perth CBD and Mirrabooka districts.

Police say he is about 166cm tall with a medium build, grey hair, grey beard and brown eyes.

Detectives from the Serious Offender Enforcement Squad are urging the public to call police immediately on 131 444 if he is spotted.

Anyone with information relating to his recent movements or current whereabouts should contact Crime Stoppers. Reports can be made anonymously.