Mandurah Detectives are investigating a suspicious fire at a development site in Golden Bay which has been the focus of angry protests this week.
The blaze was reported about 9.45pm on Wednesday with police and fire crews called to the Dampier Drive crime scene.
The site has been the subject of recent protests, with nearby residents opposing land clearing for new housing.
The fire was brought under control within half an hour, but not before it caused considerable damage to the machinery believed to be around $400,000.
Police searched the area however no suspects were found.
Detectives have asked anyone with information about the incident to contact Crime Stoppers on 1800 333 000 or report online to www.crimestopperswa.com.au.