Shark attacks in Australia are rare this summer.

Shark attacks in Australia are rare this summer.

The horrifying shark death of a 21-year-old woman has stunned the carefree holiday haven of North Stradbroke Island, east of Brisbane.

Beaches have been closed as police and fishermen search waters off the Moreton Bay island for the shark that attacked in waist deep water yesterday.

It ripped off both the woman's arms and badly mauled her torso and legs at Amity Point about 5pm (7pm NZ).

Bystanders scrambled for towels to stem the massive bleeding before a helicopter rushed the stricken woman to Brisbane's Princess Alexandra Hospital where she died.

Beaches within a two kilometre radius east and west of Amity Point have been closed and police have mounted patrols to advise holiday makers and residents.

The woman, from McDowall on Brisbane's northside, was among a group of friends from a church group swimming in waist-deep water 15 metres offshore in an area known as Rainbow Channel when the shark attacked. The woman's dog had also been in the water.

Queensland Ambulance paramedic Lachlan Parker said the woman was barely alive when they reached her.

"She had lost significant amounts of blood," Mr Parker told ABC radio.

"The patient had what we call altered level of consciousness where (we weren't) able to communicate directly with the patient."

Authorities said it was not clear what species of shark was responsible for the death.

However, South Australian based shark expert Andrew Fox said he would not be surprised if a bull shark -- a species aggressive at this time of year -- was involved.

"It may mean the bull sharks have moved into the area and are feeding and they're a pretty large, robust shark," Mr Fox told Sky News.

The fact the woman was swimming with an animal and late in the afternoon could have contributed to the shark attack, he said.

"It's known ... not to swim with animals -- I don't know how much that contributed in this particular case but it's a certainly one of the guidelines," Mr Fox said.

He denied there had been an increase in shark attacks across Australia in recent years.

"There's definitely been a bigger increase in the attention to shark attack ... with a lot of photographs being put into the media it makes us more aware," he said.