Warmer waters draw sharks to Newcastle's beaches

The swimmer raised the alarm with lifeguards about 7.30am on Wednesday along the Dixon beach stretch of coast.

People were immediately evacuated from the water and lifeguards conducted sweeps of the area between Merewether and Bar Beach.

The shark sighting in the Dixon area comes after Nobbys Beach was closed twice on the weekend when a drone spotted sharks near the swimming and surfing zones.

Surf Life Saving NSW Hunter president Henry Scruton told the Newcastle Herald this time of year and new technology could be playing a part in the string of sightings and snap beach closures.

"At the moment, our water is a little bit warmer than normal and I do believe that the big fish like the warmer water, which is possibly why they're hanging around at the moment," he said.

"They do live in the ocean, that is their home, and they get to travel up and down."

It's understood the Department of Primary Industries (DPI) confirmed the Dixon sighting on Wednesday morning.

"The sharks are always there but these drones are giving us the heads up with a lot more accuracy," Mr Scruton said.

Swimmers and surfers that choose to enter the water are unlikely to have an interaction with the creatures.

Newcastle is no stranger to sharks though, which can be unpredictable, and Mr Scruton said there are steps people can take to stay as safe as possible and enjoy the open water.

"Take caution, try to swim between the flags whilst the lifeguards are patrolling," he said.

"We've got the drones up and about as much as possible."

It's understood some beaches along the Dixon, Merewether, Bar strip had reopened by later on Wednesday morning, according to Lord Mayor Nuatali Nelmes.

After a shark sighting, life savers sweep the beaches and if it's all clear, they go out again about an hour later before considering re-opening the beaches to the public.

The water in Newcastle is about 20 degrees at the moment, sometimes warmer.

According to an online shark report network, where people can record sightings or tagged sharks are logged, there were sharks at Catherine Hill Bay and Soldiers Beach yesterday, and at Nobbys, Birubi and Redhead on January 28.