WorkSafe is investigating the work-related death of an 89-year-old farmer at Berkshire Valley - 200 kilometres north of Perth - late on Tuesday.
The farmer was reported to have been unloading hay from a tractor when the vehicle slipped into gear and rolled forward, striking him.
WorkSafe WA Commissioner Darren Kavanagh said any work-related death was a tragedy, and relayed his sincere condolences to the man's family.
"This is the ninth death in agriculture workplaces in the past year, and that figure is not acceptable," Mr Kavanagh said.
"I'm particularly concerned about farmers in the over-60 age group, as six of the nine agriculture workers who have lost their lives over the past year have been in this age group.
"Agriculture is frequently represented in the top three industries for workplace deaths, and there's an increasing need to give greater priority to safety and health.
"I have called upon agriculture industry leaders to increase efforts to change these tragic circumstances in this industry."
Sign up for our newsletter to stay up to date.