A man who was mauled by a shark while surfing south of Perth has suffered serious injuries and was due to be transferred 80km to the State Trauma Centre on Tuesday night.

The 29-year-old was attacked at Falcon Beach, a popular surfing spot, with an ambulance called at 4pm (WST).

Paramedics worked on the man on the beach for about 20 minutes before he was transferred to a waiting ambulance and taken to Peel Health Campus 13km away.

A medical team was working on the man in the emergency department to stabilise him enough so he could be taken to the Royal Perth Hospital's State Trauma Centre as soon as possible, said the hospital's chief executive Margaret Sturdy.


"He is currently in a serious condition with a serious injury, a significant shark bite and is getting a lot of medical input," Dr Sturdy told AAP.

She would not say if the injuries were life threatening or confirm if the man had lost his leg as had been speculated.

A Falcon Bay Beach Cafe worker told AAP that two men rushed in asking for ice, saying someone's leg had been bitten off.

A spokeswoman for the City of Mandurah said the beach had been closed from Falcon Bay to Westview Parade, including Yeedong Bay.

Surf Life Saving WA tweeted earlier in the day that there was a public report of a 3.5-metre white shark sighted shortly before 8am (WST) at Pyramids Beach in nearby Dawesville, about 1.8km offshore.

The last shark attack in WA was in October, when there were two incidents that resulted in minor injuries.

A grey nurse shark was probably responsible for biting 18-year-old Eli Zawadzki on the foot while he was surfing at Pyramids Beach in Dawesville.

Later that same month, a man was bitten by a shark off WA's southern coast in Albany while diving from a boat and spearfishing, suffering minor injuries.