The friends of a diver mauled by a great white shark at a popular holiday island in Western Australia attempted to save his life before he succumbed to his injuries, police say.

The 38-year-old man was spearfishing 20m from his boat, about a kilometre offshore from Horseshoe Reef near Geordie Bay at Rottnest Island, on Saturday morning.

While he was on the surface of the water, he was attacked by a shark at about 10am.

The man was transported by boat to shore at the bay on the north side of the island where he was met by St John Ambulance paramedics.

First responders desperately tried to revive the swimmer but he sadly died.

‘The victim was on the surface at the time, about 20 metres away from the vessel,’ Sergeant Michael Wear, told reporters.

‘The friends of the victim retrieved his body from the water, they gave him CPR on the way back in and came straight into the Geordie Bay jetty.

‘The friends have witnessed the horrific event.’

The attack happened at Rottnest Island, near Perth, about 10am on Saturday (the scene is pictured)
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The attack happened at Rottnest Island, near Perth, about 10am on Saturday (the scene is pictured)

An ambulance, a police car and a stretcher are seen at the scene of the fatal mauling
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An ambulance, a police car and a stretcher are seen at the scene of the fatal mauling

The incident happened at Rottnest Island, about 10am on Saturday (stock image)
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The incident happened at Rottnest Island, about 10am on Saturday (stock image)

Police said the injuries were ‘quite horrific’ but said they would not provide further detail on Saturday out of respect for the family.

A rescue helicopter arrived at the island, 19km off the coast of Fremantle, in case the man needed to be evacuated to hospital on the mainland.

A five-metre great white shark was spotted 80 metres offshore about the time of the attack, according to Surf Life Saving WA.

The Department of Primary Industries and Regional Development urged people to take extra caution in the Geordie Bay area.

‘Take additional caution in the Geordie Bay, Rottnest Island area,’ DPIRD said.

Beach-goers were asked to report any shark sightings to authorities.

Rottnest Island, which is 11km long and 4.5km wide, is a popular tourist destination.

A report will be prepared for the coroner.