Lifeguards on jet-skis have been working in teams to herd the baitfish out to sea, a technique they honed over winter.

Newcastle City Council senior beach inspector Warren Smith said the method evolved from a plan hatched last summer to remove the temptation for sharks to gather near swimmers.

He said Newcastle lifeguards would present the fish-herding technique at a life saving summit later this year.

Mr Smith said several factors came into play when directing baitfish, such as how the fish reacted to the jet-skis, the waves, different weather patterns and each other.

‘‘We’ve developed it [the herding] ourselves and perfected it over the last 12 months, and it’s really working well for us,’’ he said.

‘‘We try and move the schools of fish down towards the Bogey Hole so the sharks will move away from the swimmers.’’

The method was called into action off Newcastle Beach on Saturday to help steer away a pair of bronze whaler sharks.

The 1.5-metre predators, whose species has been known to attack humans, were spotted just before noon.

The beach’s shark siren sounded twice to warn swimmers to leave the water, and schools of fish near the shore were dispersed by jet-skis before lifeguards performed a routine grid search offshore.

‘‘We’re the only ones I know who are doing this,’’ Mr Smith said. ‘‘I’m very impressed with what we’re doing, and very happy with it.’’

A shark thought to be three metres long popped up between two surfers competing in the Catho Classic at Catherine Hill Bay on Friday, but failed to interrupt the event.

A large bull shark came within 25 metres of swimmers at a NSW south coast beach.

The lurking three-metre monster, north of Mollymook, was repelled on Saturday afternoon by an inflatable launch.