UPDATE: LIFESAVERS have rescued 30 people stranded on a rock off the Esperance coast in WA after reports of a great white shark in the area.

Surf Life Saving WA said Twilight Beach in Esperance was closed between 11.15am and 12.30pm yesterday after a helicopter tour group spotted the six-metre shark.

It said 30 people were on a rock a short distance from the shore, but rather than ask them to swim back, a boat was sent to pick them up, Perth Now reports.

"Lifesavers transported 30 people via boat from Twilight Rock to the mainland without incident,'' Surf Life Saving WA said.

It follows the sighting of several other sharks in the state's south west region yesterday including three one-metre sharks that were feeding near Margaret River.

Meanwhile, authorities and volunteers will keep a close eye on waters off the NSW mid-north coast, after a shark mauled a surfer yesterday.

The 29-year-old man's life was saved by his mates' quick thinking after the shark took one of his fingers and injured his leg while he was on a paddle board near remote Diamond Head, south of Port Macquarie.

He was flown to Newcastle's John Hunter Hospital in a serious but stable condition, as beaches in the area were closed to swimmers for 24 hours.

Surf Life Saving's state lifesaving manager Dean Storey said holiday-makers should swim only at patrolled beaches.