A woman watched her father being mauled to death by a large shark while the pair were diving off the Australian island state of Tasmania, police said.

The woman had returned to their boat with scallops the pair had collected then became concerned that her father, in his late 40s, had not surfaced, Inspector David Wiss said in the state capital Hobart.

"His daughter became worried and went down and checked on her father," Mr Wiss said. "She saw a very large shark; she saw her father being attacked by the shark."

The attack happened off the east coast near where a four and a half metre (15ft) great white shark was seen yesterday, government ranger Peter Lingard told The Examiner newspaper.

It occurred as Australian professional surfer Mick Fanning made his first return to the water since he fought off a large shark during a World Surf League competition in South Africa last weekend.

The three-time world champion went surfing alone at his hometown of Tweed Heads, 430 miles north of Sydney. He had contemplated giving up the sport after he was knocked off his board by a large shark at Jeffreys Bay. That attack was televised live around the world. He survived unscathed.

"First surf back. Feels so good," Fanning posted on Instagram.

Sharks are common off Australia's beaches, but fatal attacks are rare. The country has averaged fewer than two deadly attacks per year in recent decades.