SYDNEY: A shark killed a diver off the coast of Western Australia on Saturday (Jun 6), police said, the country's fourth fatal shark attack this year.

The man in his 30s was attacked by a 4.5m shark off Michaelmas Island, southeast of Perth, ambulance services and the Western Australian government said.

The attack was reported around 11.25am local time, they added.

Police said the man was spearfishing when he was attacked by the deadly fish and was taken back to shore where paramedics attempted to treat him.

"Sadly, he was unable to be revived," they said.

The state's Department of Primary Industries and Regional Development urged people to take "additional caution" in the area and to stay abreast of shark sightings in the area.

The attack comes just two weeks after a man was killed by a shark in northern Queensland state.

And the killing is the second this year in Western Australia - last month a man died after being attacked by a great white off Rottnest Island near the city of Perth.

Australian scientists believe increasingly crowded waters and rising ocean temperatures are shifting sharks' migratory patterns, which may be contributing to a rise in attacks.