Perth Police suspects a shark may have taken a missing swimmer at Cottesloe Beach.

Bryn Martin, 64, started swimming from the shore near the Indiana Tea Rooms on his daily swim on Monday morning. He was reportedly several hundred metres from the shore when he disappeared from sight.

Martin was a "very strong and a very good swimmer," according to his friends and family. He competed in the Rottnest Channel Swim and set the record for the oldest male duo swimmer in 2002.

A friend and several other swimmers were alarmed when he did not surface again, and fears of a shark attack started creeping in when a search into the water proved futile.

Senior Sergeant Denise Grant told News.com that Mr. Martin's speedo was found on the sea bed near the buoy several hours later.

"Police divers have located a pair of black speedo bathers that have been positively identified by our missing person's wife," she said.

Fisheries experts have examined the bathers and said the damage is consistent with that which a white pointer shark would cause.

Martin is a successful businessman and proponent of a private port in Kwinana, PerthNow reported. He is the chief executive of James Point, a company appointed by the State government to build private port facilities in Kwinana.

Despite clues of a possible shark attack, police said it was too early to rule out other possibilities.