A man has died after being attacked by a shark while diving off the coast of Esperance in Western Australia's south-east.

Key points: The man was diving from a boat when he was bitten by a suspected white shark

The man was diving from a boat when he was bitten by a suspected white shark Police and marine rescuers are still searching the ocean for his body

Police and marine rescuers are still searching the ocean for his body Warnings have been issued for the Cull Island area and patrols are planned

The man suffered fatal injuries when he was bitten by a suspected white shark near Cull Island around 1:00pm on Sunday.

Police believe the man was diving from a boat in the area off West Beach when he was attacked.

"Esperance Police and Marine Rescue WA volunteers deployed to the area on board marine rescue vessels. They are still searching the ocean for the victim," police said a statement.

"A woman who was on board the boat at the time of the incident has been returned to shore, and has been taken by St John Ambulance to hospital. She is suffering from shock.

"Police Air Wing and specialist divers from Water Police are assisting with the search."

Local Glenn Quinlivan raced to the scene on boat after hearing the mayday call.

"We found a couple of flippers and a sleeve in the water, basically that was about it," he said.

"There was nothing to see."

Western Australia's Department of Primary Industries and Regional Development (DPIRD) is also investigating and beaches in the area have been closed.

Cull Island is located several kilometres off the coast of Esperance and is a popular diving spot.

Warning issued for Cull Island area

DPIRD is urging people to take additional caution in the Cull Island area and to follow any local beach closures.

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Authorities said fisheries officers would also be conducting patrols around Esperance, which is located about 700 kilometres south-east of Perth.

Esperance Shire President Ian Mickel said it was a sad day for the region.

"I think of the thousands of people in Esperance this summer having a fantastic time swimming and snorkelling, to then have an event like this it is very disappointing," he said.

He said beaches in the vicinity of the attack were likely to remain closed until at least Monday.

"The shire closed all of the beaches immediately and endeavoured to get people out of the water anywhere they knew people were surfing or swimming," he said.

Second fatal attack near Esperance in three years

Esperance was the scene of a fatal shark attack in April 2017, when 17-year-old Laeticia Brouwer was bitten while surfing with her father at Kelp Beds, just a few kilometres from the town.

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The WA Government bowed to public pressure the following year when it announced a trial of so-called SMART drum lines to try to reduce the number of shark attacks along its coastline.

The decision to conduct a 12-month trial in waters off Gracetown in the state's South West came after two non-fatal shark attacks in the area.

The attacks near Gracetown led to the cancellation of the Margaret River Pro surfing competition and prompted uncertainty about the future of the event.

The Government had previously resisted the drum line technology and had supported personal shark deterrents instead.

The Esperance Ocean Safety Group, which has campaigned for stronger action to minimise the shark threat, said it was frustrating that more had not been done in its region in response to previous attacks.

"It was only a matter of time, there have been so many [sharks] hanging around lately," the group's Mitch Capelli said.

"History is going to keep repeating itself unfortunately."

There have been 16 fatal shark attacks in WA since 2000.