Stingray barb through the heart kills Crocodile Hunter Steve Irwin

The 44-year-old, known around the world for his love of crocodiles, died during a diving expedition when he was attacked by one of the dangerous stingrays and received a deadly barb through his heart.

Irwin was filming an underwater documentary on the Great Barrier Reef in north-eastern Queensland state when the accident occurred.

The Australian Broadcasting Corporation said Irwin was diving near Low Isles, close to the resort town of Port Douglas, when the incident happened.

A helicopter carrying paramedics flew to the island, but he died from a stingray barb to the heart, it was reported.

Irwin is famous for his enthusiasm for wildlife and his catchphrase "Crikey!" in his television program, Crocodile Hunter, which was first broadcast in Australia in 1992 and has been broadcast around the world on the Discovery channel.

He rode his image into a feature film, and developed the Australia Zoo as a tourist attraction.

But Irwin's public image was tainted in 2004 when he triggered a public outcry by holding his baby in one arm while feeding large crocodiles inside a zoo pen.

Irwin claimed at the time there was no danger to his son, and authorities declined to charge Irwin with violating safety regulations.

Later that year, he was accused of getting too close to penguins, a seal and humpback whales in Antarctica while making a documentary. Irwin denied any wrongdoing, and an Australian Environment Department investigation recommended no action be taken against him.

His friend and producer John Stainton today said Irwin "died doing what he loved best".

Australia Zoo, the wildlife park Irwin ran in north-eastern Queensland state, issued a statement confirming he was killed today "by a stingray barb to his heart" while filming a sequence for a new television series on the Great Barrier Reef.

Irwin was stung at about 2am today on Batt Reef. Crew members on Irwin's boat, Croc One, called emergency services in the nearest city, Cairns, and administered cardio pulmonary resuscitation techniques as they rushed the boat to Low Isle to meet a rescue helicopter.

Medical staff pronounced Irwin dead a few hours later.

Local diving operator Steve Edmondson said: "Steve was hit by a stingray in the chest. He probably died from a cardiac arrest from the injury."

Fellow-Australian wildlife filmmaker David Ireland said he was shocked and saddened by Irwin's death, adding that a stingray's barb could be as deadly as a rifle bayonet. "They have one or two barbs in the tails which are not only coated in toxic material but are also like a bayonet, like a bayonet on a rifle," he said. "If it hits any vital organs it's as deadly as a bayonet."

Friend John Stainton added: "The world has lost a great wildlife icon, a passionate conservationist and one of the proudest dads on the planet.

"He died doing what he loved best and left this world in a happy and peaceful state of mind. Crocs rule!"

Australian Foreign Minister Alexander Downer, who used a photograph of his family at Australia Zoo for his official Christmas card last year, hailed Irwin for his work in promoting Australia through projects such as the "G'Day LA" tourism and trade promotion in Los Angeles in January. "The minister knew him, was fond of him and was very, very appreciative of all the work he'd done to promote Australia overseas," Mr Downer's spokesman Tony Parkinson said.

No-one at Australia Zoo was available for comment today.

Irwin is survived by his American wife Terri Irwin, from Oregon their daughter Bindi Sue, eight, and son Bob, who will turn three in December.