A man has been arrested after allegedly pointing a gun at a tug boat crew near Kwinana Beach.
The man was in a dinghy near the Kwinana Port when he allegedly pointed a firearm at the crew about 6.30pm on Sunday.
The accused then allegedly fled the area in his vessel towards Garden Island in Rockingham.
It's understood the firearm was not discharged.
The police air wing and water police were deployed after the tug boat crew reported the incident.
About 7.30pm, water police found the man in the dinghy in waters off the Rockingham jetty.
He allegedly failed to stop and collided with the police boat before leaving the scene.
"Following a further search, a 48-year-old man was arrested near Garden island about 8.30pm. His dinghy was seized," a WA Police spokesperson said.
He was charged with unlawful act or omission with intent to harm (endangering life, health or safety of any person, and being armed in a way that may cause fear.
The High Wycombe man is due to appear in the Rockingham Magistrates Court today.
Nobody was injured during the incident and inquiries are continuing with Mandurah Detectives.