Ten years ago, and nearly two decades after the infamous Lindy Chamberlain case, a boy of nine was killed by two dingoes on an island in Queensland – grim proof that Australia's native dogs do attack children. The fatal mauling of Clinton Gage, at the popular tourist destination of Fraser Island, caused national outrage and silenced those who had scorned Ms Chamberlain's claim that a dingo had snatched her baby daughter, Azaria, as they camped out at Uluru in 1980. The Queensland government took drastic steps to protect visitors, culling dozens of animals on Fraser and fencing off resorts and camping grounds.

Now critics say the clampdown has gone too far and that Fraser Island's dingoes, accustomed to scavenging in rubbish tips, are dying of starvation. Some conservationists are even warning that the animals could go the way of the thylacine, or Tasmanian tiger, which was hunted into oblivion in the 1930s after being blamed for livestock deaths.

Fraser, the world's biggest sand island at about 75 miles long, had a thriving population of dingoes long before tourists arrived. Like their mainland counterparts, local Aborigines valued the animals as companions, hunters and watchdogs. The island is home to one of Australia's purest remaining dingo strains, and despite Clinton Gage's death in April 2001, the wild dogs remain a major attraction. Wildlife officials are under strict instructions to limit encounters between humans and dingoes, however. Anyone caught feeding the animals faces a heavy fine, and rangers continue to destroy dogs that display aggressive behaviour. Twenty-eight were shot after the attack on Clinton, who was camping on the island with his family.

Banished from populated areas, many of Fraser's 200-plus dingoes are starving, their advocates say. They also believe the introduction of ear tagging has made the dogs less effective hunters, while the practice of "hazing" them – firing clay pellets to move them off beaches – causes injuries and stress. Ian Gunn, a veterinarian at Monash University in Melbourne, says: "When you see the condition of these animals... if I owned them, I would be prosecuted for animal cruelty. If this continues, the dingoes on the island will become extinct."

The Queensland Parks and Wildlife Service insists such fears are unfounded. It also denies the dogs are short of food, saying they are naturally lean, with a high mortality rate among pups. "Dingoes are still widespread across Fraser Island, they are breeding very effectively," says Terry Harper, the wildlife service's senior director of marine parks. "As a population, they are in very good condition."

The ancestors of the dingo were introduced to Australia about 4,000 years ago by Asian seafarers. On the mainland, interbreeding with domestic and wild dogs has led to increasing hybridisation, but on Fraser the isolated population has remained genetically pure.

Recently, controversy has crystallised around Jennifer Parkhurst, a wildlife photographer who was fined A$40,000 (£24,730) and given a nine-month suspended sentence for feeding and "disturbing" dingoes. Ms Parkhurst, a founder of the Save Fraser Island Dingoes group, had spent years observing the animals. But while she has become a martyr figure, not all conservationists support her. The Fraser Island Defenders Organisation, set up in the 1970s to oppose sand mining, disputes that dingoes are under threat. It believes supplementary feeding of them would be "disastrous", triggering a population explosion and destroying the traditional pack structure. Critics of the separation of humans and dogs on Fraser – who include Bob Irwin, father of the late "Crocodile Hunter" Steve Irwin – point to the dingoes' co-existence in the past with the indigenous Butchulla people. But Mr Harper says the island's 350,000 annual visitors cannot be expected to know how to interact with them safely.

Dr Gunn, vice-president of the National Dingo Preservation and Recovery Programme, rejects Mr Harper's assertion that the Fraser dingo population is healthy. He believes there are only 40 to 50 breeding animals. Post-mortem tests on 90 dogs, obtained via freedom of information searches, show that most died of starvation.

In Europe and the US, says Dr Gunn, confrontations between campers and wild bears have been minimised by the establishment of feeding stations. He also suggests that problem animals could be relocated to mainland reserves. "This is a world heritage site and the authorities looking after it have a moral responsibility to protect the flora and fauna. I fail to see that that is happening."

Both sides of the debate brandish photographs showing, variously, healthy looking or emaciated dingoes. Karin Kilpatrick, secretary of Save Fraser Island Dingoes, says the removal from the island of wild horses known as "brumbies" – previously a food source for the dogs – "created a hunger situation". That, and a sharp increase in tourism, led to problems never before experienced, Ms Kilpatrick says. "Tour operators say they are seeing very few, and those that they see are lacklustre in their fur and they look depressed," she says. "Some have diarrhoea or are limping – we believe that's because they are having to travel long distances to find food."

The autopsies showed that dogs' stomachs were empty, or contained just sand or grass or plastic waste. To that, Mr Harper responds that a domestic dog's stomach would be empty an hour before its daily meal. He says the dingoes' main problem is "habituation" – growing accustomed to humans as an easy food source, and then turning dangerous.

Dr Gunn disagrees, saying starving dogs are more likely to enter populated areas. He is adamant that Fraser's dingo population is ailing. "Australia has lost more than 20 native mammal species since European settlement, and it's still continuing," he says.

The 'dingo baby' case

In 1980 Lindy and Michael Chamberlain went camping in the Australian outback. On 17 August they reported that their nine-week-old daughter, Azaria, had been snatched from their tent by a dingo, but police did not believe them.

Mrs Chamberlain was jailed for life after a seven-week trial in 1982. Her husband received a suspended sentence.