Rock fisherman dies off Sydney's Northern Beaches

A rock fisherman has died after being swept into the water off Sydney's Northern Beaches early today.

He was one of three who men were fishing near Blue Fish Point, Manly, when one of them was swept away and two others – who were wearing life jackets – jumped into the water to help, police said.

Police were alerted to the emergency about 6.30am and pulled all three men from the water.

One man, aged 23, could not be revived, and the two others, aged 31 and 36, were taken to hospital.

"One patient was in cardiac arrest and was assessed by the doctor and paramedic and was deemed to be deceased," NSW Ambulance Inspector Giles Buchanan said.

"The other two patients had significant immersion and hypothermia and have been transported to St Vincent's Hospital in a stable condition."

Meanwhile, another fisherman was rescued after falling from rocks at Cape Solander near Kurnell about 7am.

He was not wearing a lifejacket but was able to stay afloat after another angler threw him an 'angel' ring flotation device.

The 20-year-old fisherman was then taken to St George Hospital.