Shark clamps onto Hawaii surfer's hand

A Hawaii woman has escaped a tiger shark attack with injuries to her fingers and hand after her friend punched the animal until it relented.

Surfer McKenzie Clark left hospital last week after getting 20 stitches on her left hand, middle finger and ring finger.

The ring finger, scraped to the bone, will require a skin graft.

"Its intent was to eat my friend right in front of me, and I wasn't going to let that happen," Brian Wargo said.

Clark was paddling her surfboard in murky waters in the Big Island's Keawaeli Bay.

Wargo saw Clark and her board on top of the shark's back. He said he expected the attack to be over by the time he reached her.

"When I paddled out to go to her, I wasn't thinking I was going to get into a battle with a shark," he said.

The shark clamped onto Clark's hand and board. She was able to free her hand and rolled off the board, but the shark kept the board between its teeth, towing Clark by the leash that attaches to a surfer's ankle.

Wargo grabbed the dorsal fin with both hands, pulled the shark off the board and started punching it between the gills and dorsal fin.

"I hit it probably four times and it just kept going at her," he said.

"I hit it as hard as I could. I thought my hand was going to break."

He said he could tell his final hit landed when the shark shuddered.

Wargo, the captain of Bite Me sport fishing charters, said he suspects it was a three- to four-metre tiger shark.