A teenage girl in New Zealand bashed an attacking shark over the head with her body board until it let her go.

Lydia Ward, 14, was in waist-deep water with her brother at Oreti Beach, on New Zealand's South Island, when the shark grabbed her hip.

She said she did not notice the shark until the attack was under way.

"I saw my brother's face and turned to the side and saw this large grey thing in the water, so I just hit it on the head with a boogie board," Ward told National Radio.

Explaining how she had read about a surfer who fought off a shark attack with her board, Lydia said: "That's what she did, and that's what you're meant to do."

The siblings fled from the water after the attack.

Lydia added: "I showed Dad and he didn't really believe me. But then I showed him my wetsuit, with all the blood coming out, and he believed me."

The girl's mother Fiona Ward said the shark's bite had ripped Lydia's wetsuit and penetrated her skin, but the teen did not need stitches.

Marine scientist Clinton Duffy said the shark was probably a broad-nosed seven gill shark.

The species grows to up to 10 feet long and has attacked swimmers at the Oreti Beach in the past.

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