Surf Life Saving Illawarra duty officer Lachlan Pritchard said a surfer had approached lifesavers at North Wollongong Beach about noon yesterday.

As a result, the Bendigo Bank Aerial Patrol conducted four passes between North Wollongong and Towradgi Point, but no shark was spotted from the air.

Mr Pritchard said it was extremely rare for a shark to come in so close to populated beaches.

"Down at Port Kembla there are a couple of sightings around the port, but normally they're a little further out," he said.

"Normally they're not spotted by swimmers or surfers; it's usually by the aerial patrols."

Bendigo Bank Aerial Patrol manager Harry Mitchell said shark sightings tended to become more frequent around the Illawarra as water temperatures increased.

"We see quite a number of sharks throughout the summer season. Sharks tend to congregate where there are plentiful supplies of food for them," Mr Mitchell said.

The last reported shark attack in the Illawarra was in January 2009, when Windang man Steve Fogarty was attacked by a dusky whaler shark while snorkelling near the Windang boat ramp.

In April 2010, a great white shark was spotted in Lake Illawarra.

Mr Mitchell said hot spots in the Illawarra included Port Kembla, as well as the notorious "shark alley" around beaches north of Austinmer. Estuaries were also considered prime shark territory, with many marine animals gathering to feed off nutrients flowing downstream.

As well as looking out for sharks, Mr Mitchell said patrols were constantly keeping an eye out for large schools of fish, which attracted larger predators.

"If the Bendigo Bank Aerial Patrol spots a shark, immediately we relay that info to the beach safety providers," he said.

"If it's a matter of urgency and there's an immediate threat we'll activate the siren, then speak to the beach safety providers."