Ambulance workers said the 21-year-old suffered extensive injuries, losing both arms below the elbow and sustaining deep wounds to her leg.

Police suspect that several sharks carried out the attack, which happened on North Stradbroke Island.

The victim was thought to have been swimming in shallow water with a local church group when she was attacked.

Friends carried Sarah Kate Whiley from the water and she was quickly flown to hospital by helicopter.

However, she had lost large amounts of blood and had gone into shock. She died later in hospital.

Aggressive

The attack happened at Amity Point, which shares a name with the fictional setting for the film Jaws.

Police believe three bull sharks could have attacked the young woman, and have launched a large-scale hunt in local waters.

We've always thought someone was going to be taken here

Miles Scott

Fisherman

"If we found them I suppose we would try to retrieve them and see if they have any body parts," said Queensland police inspector Ray Harding.

"Realistically it's virtually impossible [but] the idea is to retrieve what we can."

Local fears

The victim was swimming with friends and her dog about 15m (49ft) offshore when she was attacked in water which had become murky and muddy after a storm on Friday night.

Locals near the site of the attack, on Amity Beach, said they often saw sharks in the water, and had been concerned about a possible attack.

"We've been waiting for this for a long time," said fisherman Miles Scott.

"We've always thought someone was going to be taken here."

There have been 10 fatal shark attacks in Australian waters in the past five years.