There have been no sightings, but all the signs point to a massive shark lurking in the waters off Brisbane.

Queensland's fisheries department is warning beachgoers about a five-metre great white.

A baited drum line hook, used to catch large sharks near Stradbroke Island's swimming beaches, was bent almost straight.

Tony Ham, the manager of the Shark Control Program for Fisheries Queensland, says the shark had the power to reshape the 13 millimetre-thick hook and break free.

"Queensland Shark Control Program uses a range of baited drum lines and fishing nets at selected beaches throughout the state to try and reduce the number of sharks that move in and out of our popular swimming beaches," he said.

"It's not designed to catch every shark, and indeed we specifically, with the equipment, try and target sharks over two metres which are considered to be those that pose most risk to swimmers.

"So what we are trying to do is just reduce that risk of swimmers coming into contact with dangerous sharks."

Mr Ham says swimmers need to be aware of the dangers.

"Even quite large sharks will come in waste or hip-deep water looking for food if there is a food source is available," he said.

"So they will come in quite close. Generally we find that most sharks travel along the beach where they can be stealthy if you like, that is their nature."

But locals on Stradbroke Island say the State Government needs a reality check.

Russell Specht has lived on the island all his life and says he has been annoyed by the media coverage.

"Fair enough it is a frightening thing to see a baited hook of that size actually straightened and everything, but I have got my doubts on it," he said.

"It was actually done last month or last week or last year sort of thing because we had the same thing happen this time last year sort of thing and ... it was bitten in half."

Mr Specht says authorities and beachgoers need a reality check.

"If you sat a helicopter up there for three hours or something like that, I am sure you would actually see a lot more big bities go past too," he said.

"One actually went past and when that went past last week, in the last week alone you'll probably see three or four sharks a week on an average."

Mr Ham acknowledges big sharks are common off Stradbroke Island and admits it has more than likely moved on.

"Our understanding of their behaviour, it's probably headed south by now - not too keen on warmer water temperatures, so the reality is it has probably headed off back to the Southern Ocean with some luck," he said.