Emergency services were called at about 4.35pm local time on Wednesday to Buchan Point, Malabar, following reports of an attack that caused "catastrophic injuries" to the victim.

Witnesses told local television they had seen the attack on a swimmer wearing a wetsuit.

It was the first fatal shark attack in Sydney since 1963, according to data.

"Some guy was swimming and a shark came and attacked him vertically," witness Kris Linto told Nine.

"We heard a yell and turned around - it looked like a car had landed in the water."

Another witness estimated the shark was 4.5m (16.4ft) in size.

The police offered no information about the identity of the swimmer.

A New South Wales Ambulance spokeswoman said paramedics were called to Little Bay, adding that "unfortunately this patient had suffered catastrophic injuries and there was nothing paramedics could do".

The New South Wales state government has spent millions of dollars on technology in an attempt to reduce shark attacks along its coast.

It has deployed nets at 51 beaches, as well as drones and shark listening stations that can track great white sharks by satellite and send an alert when one is sighted.