Construction workers at Madora Bay have been threatened by a man who entered a work site with two guns.
Police said the man threatened workers with a loaded shotgun and a pistol.
Nine News reports the man allegedly drove onto the construction site at Madora Beach Road on Wednesday night just as workers were about to go home and pointed the guns at them.
He then stole a work ute, leading police on a chase through Madora Bay that ended at Mandurah police station where he got out and was arrested without incident.
A 23-year-old man has been charged with a number of offences, including armed robbery.
Wormall Civil is offering its employees counselling.
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