Local fire crews were called out to a number of grass tree fires in Dawesville overnight.
Falcon Volunteer Fire and Rescue attended the fires on Estuary Road around 1.30am on Friday.
Mandurah Police also patrolled the area.
Anyone who saw any suspicious activity in the area at the time is urged to contact Crime Stoppers on 1800 333 000.
Mandurah to shine bright this Christmas
Secret Harbour Beach closed due to shark sighting
Rockingham named a hotspot for dog attacks on posties
Desperate plea from family of critically ill toddler
Motorcyclist dies in Oakford crash
Fire destroys Waikiki granny flat
Longer retail trading hours for Mandurah this Christmas
Christmas on the Murray returns
Local sports stars honoured at 2025 Mandurah Sports Awards