Newcastle beaches might shut for sixth day over giant shark sightings

Newcastle beaches could remain closed for a record six days with repeated sightings of a large great white shark again keeping swimmers out of the water.

The five-metre shark, first spotted on Saturday afternoon at Merewether Beach, could bite a person in half, Nobbys Beach inspector Paul Bernard told AAP.

"You don't get a second chance with these things," he said.

The shark was last seen by water police early Tuesday afternoon at Burwood Beach and has been sighted in an area stretching 10 to 12 kilometres.

Helicopters have also been combing waters off Newcastle but didn't spot the shark during a search late that same afternoon.

Overcast and warm weather combined with increased marine activity could be responsible for the shark's prolonged presence.