“WELCOME to pain, welcome to sadness, welcome to grief,” Murabuda Warramarrba said.

The grandfather of “Johnno” Warramarrba was speaking at the 15-year-old’s funeral on Groote Eylandt in the Australian Gulf of Carpentaria last week.

As a didgeridoo played, 200 mourners sat under the shade of gum trees, listening to the Angurugu Anglican Church service.

But Johnno’s death did more than attract the local community to his graveyard. It sparked a furious debate across Australia and within the United Nations in New York about the rights of mandatory sentencing for young people.

For Johnno was a thief who had been sent to jail for stealing some pens. Despite his youth, he was automatically sentenced to 28 days in Darwin’s youth detention centre. Three weeks into the sentence, he hanged himself.

In the Northern Territory and Western Australia, laws oblige the courts to send young offenders to prison.

A person convicted of a first offence against property is jailed for at least 14 days. Three months is given for a second conviction and 12 months for a third.

The “three strikes and you’re in” law in Western Australia makes a 12-month sentence mandatory for all offenders if convicted a thir time for home break-ins and burglary.

These laws appear to be mainly directed at young Aboriginals and Johnno Warramarrba was only the latest teenager to go to prison for what in other states would have been regarded as a minor offence.

Alarmingly, two more bored juveniles on Groote Eylandt attempted suicide in the aftermath of his death, while a 22-year-old last week became the third Aboriginal in a month to be imprisoned - for the theft of a box of biscuits.

Out of school, out of work, lacking traditional behavioural controls, young Aboriginals often turn to petrol sniffing and alcohol - and even death - as a way of escape.

Now the United Nations High Commissioner on Human Rights, Mary Robinson, will investigate the mandatory sentencing laws to see if they are in breach of the UN convention on the rights of the child, to which Australia is a signatory.

Prime Minister John Howard refuses to use the Commonwealth’s powers and override the territory legislation, saying it is a matter of states’ rights. He also says he will not be pressured into taking any action by the UN investigation. But the Law Council of Australia believes mandatory sentencing breaches Australia’s international obligations.