Beach goers are being warned of a monster shark lurking in waters off Stradbroke Island in southeast Queensland.
While there have been no sightings, authorities say there is evidence a shark more than 5m long, most likely a Great white, is in the area.
A shark hook off Stradbroke Island’s Main Beach has triggered the fears after routine equipment checks found it had been bent with such force that it was almost straight.
The hook - 13mm thick, 36cm in length and 16.5cm across the gape - is part of a baited drumline system used to catch large sharks near popular swimming beaches.
Primary Industries and Fisheries Minister Tim Mulherin said it must have snagged a massive shark that had the power to reshape the hook and break free.
"The force needed to straighten a hook of this size would be immense," Mr Mulherin said.
"A shark capable of doing this would likely be in excess of 5m in length, as we have caught fish up to 5m in size on the gear previously and held them.
"This means at least one 5m white pointer is lurking off the coast of Stradbroke Island."
Swimmers are being warned to take precautions and swim in only patrolled beaches between the flags.