The larger-than-life Irwin, 44, known for his fearlessly enthusiastic handling of even the deadliest of wildlife, was killed when a stingray barb punctured his heart during underwater filming off northeastern Australia.

"He came over the top of a stingray and the stingray's barb went up and went into his chest and put a hole into his heart," said the ebullient Irwin's longtime producer John Stainton, who was with him at the time.

"It's likely that he possibly died instantly when the barb hit him, and I don't think that he ... felt any pain," a tearful Stainton told reporters in the city of Cairns. "He died doing what he loved best."

Police and officials at Irwin's zoo confirmed his death in the freak incident that took place at about 11:00 am (0100 GMT) off the coast of Port Douglas in the northeastern Australian state of Queensland.

Irwin brought to the surface unconscious and underwent cardio-pulmonary resuscitation, Stainton said.

He was evacuated from his research vessel by helicopter but ambulance service officials said he had suffered a puncture wound to the left side of his chest and was pronounced dead on the scene.

Stingrays have several sharp and venomous barbs on their tails that they use to defend themselves when they feel threatened, but Stainton insisted that Irwin had not provoked the creature while filming.

"I have never met a more professional person in my whole life nor a more passionate person in my whole life on wildlife issues," Stainton said of the iconic Irwin, who was making a show about deadly sea dwellers.

But experts stressed that stingrays were not usually vicious and rarely attacked and killed humans, unlike the range of deadly creatures Irwin had confronted in the past.

"You think about all the documentaries we've made and all the dangerous situations that we have been in, you always think 'is this it, is this a day that maybe his demise?'," he said, adding that nothing scared Irwin.

Australian wildlife filmmaker David Ireland said that the stingray's tail was "like a bayonet on a rifle". "If it hits any vital organs it's as deadly as a bayonet," he said.

Police said Irwin's US-born wife Terri had been informed of his death while hiking in Tasmania. The couple had two children aged eight and three.

The garrulous animal-lover's rallying cry of "crikey" when faced with a crocodile, snake or ferocious-looking spider made him an Australian icon across the world.

His "Crocodile Hunter" show, in which the tousle-haired adventurer appeared in his trademark khaki shorts and shirt, was first broadcast in 1992 and has been shown around the world on the Discovery cable network ever since.

His outspoken persona became so popular that he won a cameo role in a Hollywood movie, "Dr Dolittle 2," starring US comic Eddie Murphy.

Australians mourned the loss of one of their most famous countrymen, with Prime Minister John Howard leading the public outpouring of grief over the death of a man whom he knew well.

"I really do feel Australia has lost a wonderful and colourful son," Howard said. "He took risks, he enjoyed life.

"He brought immense joy to millions of people, particularly to children, and it's just such a terrible loss. He was one of those great quintessential Australian faces that people recognised everywhere," added the grim-looking prime minister after parliament was told of his death.

Ordinary Australians called into their local radio and television stations expressing their shock and sadness at Irwin's passing, while others flocked to the television star's Australia Zoo in Beerwah, on the Sunshine coast of Queensland state, to lay flowers in his memory.

"We just thought he was a good guy for what he did for Australia. He put us on the map, I reckon," said Rod Cameron at the zoo.

Another mourner was more sanguine. "He died doing what he loved, didn't he?" said tourist Glenn Batson.

The son of a plumber who launched his own reptile park, the young Irwin became a crocodile trapper, ridding residential areas of their reptilian threats before eventually taking over his parents' park.

His fearless approach to the animal kingdom however provoked international outrage when he involved his infant son in one of his death-defying antics.

In early 2004, he fed a four-metre (13-foot) crocodile with one hand while clutching his baby son Bob in the other during a show at his Australia Zoo reptile park.

But Irwin was unrepentant when confronted about the incident in an interview. "I will continue to educate my children and the children of the world so they don't go into the water with crocs," he said.

Irwin's voice remained on the answering machine of his zoo on Monday, reminding callers with a whoop: "Remember, they rule," referring to his dangerous documentary subjects.

Related Links
Darwin Today At TerraDaily.com