A three-metre shark has been spotted off Secret Harbour Beach.
The Surf Life Saving helicopter sighted the shark around 11.25am on Thursday about 70-metres offshore.
It is tracking north.
Beachgoers are advised to be extra vigilant when entering the water.
SLS Westpac Heli report 3m unknown sp. shark sighted 11:24hrs 13/04, Secret Harbour Beach, north of Mandurah 70m offshore , TRACKING NORTH.
— Surf Life Saving WA (@SLSWA) April 13, 2017
Early voting for Secret Harbour by-election begins Monday
Welfare concerns for missing Swedish national last seen in Warnbro
Wanted man last seen in Golden Bay
Passenger critically injured in West Pinjarra crash
Unregistered painter fined for requesting hefty deposit from Singleton homeowner and not doing the job
Police hunt driver following dangerous Baldivis pursuit
Welfare concerns for boy last seen at Port Kennedy skate park
Rubbish truck catches fire in Baldivis
Driver injured in bus crash in Rockingham