WA police officers riding new unmarked motorcycles have issued 147 fines to drivers using mobile phones while driving in their first week on the road.

After successful trials over the last Christmas and Easter periods, a permanent fleet has begun patrolling Perth roads.

Inattention killed 22 people and seriously injured another 41 on WA roads this year.

Assistant Police Commissioner Nick Anticich said the problem was widespread.

"Anyone here in WA only has to drive down any given road on any given day, and almost inevitably you will see someone using a mobile phone," he said.

"It is almost epidemic in proportion and we need to do something about it."

He said offending drivers often see police vehicles before an officer sees them, and quickly put their devices down before they are caught.

"These [unmarked motorcycles] give our officers a tactical advantage in that often the person doesn't realise they're a police vehicle or a police officer until it's too late," said Mr Anticich.

The bikes have lights and sirens, and officers' helmets are fitted with small cameras.

"If we see an offence, we just press the button, and this camera runs on a loop, [so]we've got a minute of what we actually saw prior to the offence being committed," said First Class Constable Eri Ikhaazali.

A total of 179 people have been killed on West Australian roads this year, 26 more than the same time last year.