Worker was struck and killed by machinery at the Mitchell Fwy road construction site in Perth's north

A construction worker was killed when he was struck by an excavator at a road construction site in Perth's northern suburbs.

The incident happened just before midday at the Mitchell Fwy's southbound exit to Warwick Rd in Greenwood.

“The man was reportedly struck by a piece of falling equipment,” WorkSafe said.

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The 35-year-old worker suffered serious head injuries and was taken by ambulance to Royal Perth Hospital, where he died a short time later, according to The West Australian.

The WA branch of the CFMEU said it was the 10th construction site fatality in the state this year.

“Our investigation has only just begun,” the union said.

“We know the incident involved an excavator and lifting equipment (but) we will not speculate on the tragic circumstances until we have the facts.

“All we know is that tragically one worker did not return home today.”

The exit was closed to motorists for six hours and emergency services attended the scene before it reopened at around 6pm.

WorkSafe investigators are now investigating how the fatal incident occurred “to ensure compliance and prevent future incidents of a similar nature.”

WorkSafe officer Sally North said work-related deaths were a tragedy and offered her condolences to the man's family.

A report will be prepared for the coroner.