Firebugs are once again in the sights of WA Police as part of the annual operation aimed at stamping out arson.

Strike Force Vulcan has been launched with police vowing to patrol fire hotspots and keep an eye on known arsonists this bushfire season.

Just over one-third of all bushfires in WA are deliberately lit.

Emergency Services Minister Joe Francis says arsonists need to be stopped.

He spoke with Adam Shand.