A Mandurah man has had a terrifying encounter with a two-metre shark off Town Beach.
Speaking to West Coast Radio, Brian Osmon said he was out for his usual jet ski ride just after 7am on Wednesday morning when the incident happened about 100m offshore.
"I was just idling along the yellow markers and the next thing you know a dorsal fin popped up next to me," he said.
"I thought 'oh a dolphin', looked down and it wasn't a dolphin, it was a lot bigger.
"It sort of swung over and nudged the side of the jet ski...it rocked the jet ski.
"From there, I don't know what happened because I put the pedal to the metal and got out of there."
Brian said he suspected the shark was a bronze whaler.
Town Beach has since been closed.
"To reduce the threat to people, Town Beach has now been closed by City of Mandurah and it will continue to reassess the situation," a Department of Primary Industries and Regional Development spokesperson said.
If you see a shark, report it to Water Police on 9442 8600.