A man has been attacked by a shark while surfing at Iluka Beach on the NSW north coast, the Department of Primary Industries (DPI) has said.

The 35-year-old man from Suffolk Park was hit from underneath his board about 6.30am by what he believed to be a great white shark.

The impact caused the board to snap and he was thrown into the air.

The surfer said the shark then began to circle and turn away, so he grabbed half of his surfboard and swam to shore.

Friends then drove him to Ballina Hospital where he was treated for lacerations on his right hip. He has now been transferred to Lismore Hospital.

Main and Bluff beaches have now been closed as a result of the attack and the DPI have activated their shark incident response plan.

The man’s board was snapped in the attack at Iluka Beach. Photo: Amber Hopkins/ABC

‘This man is lucky to be alive’

A shark biologist will assess the man’s injuries and damage to the surf board to try to determine the size and species of the shark involved, the DPI said.

A witness to the attack, Amber Hopkins, said: “This man is lucky to be alive.”

NSW Surf Life Saving said the Iluka Beach was unpatrolled and considered closed.

The NSW government introduced nets to five beaches on the North Coast in December 2016, after a spate of concentrated shark attacks.

There were 14 swimmer and shark interactions off the NSW far North Coast in 2015-16, according to the DPI.

Along with nets, 35 SMART (Shark Management Alert in Real Time) drumlines were being used between Evans Head and Lennox Head to mitigate shark attacks.

-ABC