Police have lauded the courage of two surfers who brought their mate to shore as he died from horrific injuries inflicted by a suspected great white shark at a popular West Australian surf break.



The victim, 21, was in the water in "perfect shark conditions" at The Boneyards break, Bunker Bay, in the state's south-west, when he was mauled early yesterday afternoon.



At least five other surfers were just metres from the victim but the shark struck so swiftly nobody saw the attack, said Sergeant Craig Anderson, from Dunsborough police.



The shark, reportedly up to 4.5 metres long, left the bodyboarder with terrible wounds. One report said he was missing several limbs.



His mates pulled him to shore but he died on the beach, shocking a lunchtime crowd at the nearby Bunkers Beach Cafe.



"You've got to take your hat off to the young fellow who was surfing with him and his mate for bringing [the victim] ashore. The nature of his injuries was significant. It's not something that even volunteer rescuers or emergency services like to see," said Sergeant Anderson.



The attack occurred in an area popular with surfers and anglers and close to a seal colony, to the west of Cape Naturaliste, a noted whale-watching spot about three hours' drive south of Perth.



"You could have described it as perfect shark conditions . . . dark and gloomy water, overcast skies, light rain falling. There was whale action earlier in the morning in the bay, and there were seals about," Sergeant Anderson said.



Authorities have confirmed the 21-year-old victim, originally from Sydney, had been based in Wilyabrup, near Margaret River, for several years. They are in the process of contacting his next-of-kin. The man's girlfriend is believed to have recently travelled overseas.



Dunsborough man Kurt Morris was having lunch at the Bunker Bay Cafe with his family when he saw chaos erupt on the beach.



Mr Morris said he spoke to the surfers who were just metres from the attack.



"There were three blokes from Bunbury. They were next to him when it happened," he said.



"They were saying they were just two metres away from him.



"From the waist down, it was just all gone."



Mr Morris said the group that pulled the man from water were shaken.



He said surfers were sprinting out of the water to their cars and driving to nearby surfing breaks to raise the shark alarm.



The attack was believed to have happened about 50 metres from the shore.



"It was not that far off the shore. No one is going back in the water," Mr Morris said.



Sergeant Graham Clifford said police and ambulance arrived at the beach shortly after the attack at 1.26pm (5.26pm Sunday, NZ time).



Dunsborough surf shop owner Enrique Hillman said the town had gone eerily quiet since the incident.



He said those who came in had all been talking about what had happened.



Mr Hillman, who had been surfing at Sugar Loaf Rock yesterday, said in the year and a half he had spent surfing in the area, he had seen just one shark at the site of the attack.



He got out of the water before he could get a better look at it, but said there were two seals near the shark, which was what had probably drawn it to the area.



"There's a seal colony just next to the lighthouse, there's a channel the seals use along there,” Mr Hillman said.



Shire of Busselton president Ian Stubbs said he had lived in the area for 21 years and had never seen a shark attack at the spot.



''The last shark attack I remember was in Gracetown,'' he said.



"But I can't recall the last time a shark attacked someone in this community.''



The attack happened about an hour's drive from Gracetown, where 31-year-old Nicholas Edwards was killed by a shark on August 17 last year.



Yesterday's attack is the third fatal shark mauling in Australia in just over 12 months, and the second in WA's south-west.



In February, an abalone diver was taken by two sharks, believed to be great whites, at Coffin Bay, South Australia.



- WA Today, with AAP and Lee-Maree Gallo

WA Today ATTACK SPOT: Bunker Bay, West Australia, where the shark attack occurred.