There is a huge disparity between the way Indigenous and non-Indigenous people are sentenced by Australia's justice system, according to the man charged with advocating for the rights of Indigenous people.

Aboriginal and Torres Strait Islander social justice commissioner Mick Gooda has lashed the justice system after a sentence handed down yesterday in the NT Supreme Court to a Darwin man who was involved in a hit and run.

Matthew Alexander was given an 18-month suspended sentence and six months in home detention for the incident, which killed eight-year-old Indigenous boy Jack Sultan-Page.

Mr Gooda said he found that "hard to comprehend" and that he was troubled by it.

He said it seemed to be light for the crime, "compared to what happens to our people".

"In the Northern Territory there's people being locked up for breaching an alcohol protection order, there are paperless arrests where people haven't even done anything and are put in jail," he said.

Indigenous Australians make up 86 per cent of the adult prison population in the Northern Territory, according to 2013 figures from the Australian Bureau of Statistics.

Mr Gooda said it was "hard to get away from making the conclusion" that there appeared to be different laws applied to Indigenous and non-Indigenous people, especially given Alexander's sentence.

Jack Sultan-Page died after being struck by a ute in Moulden, Palmerston, while riding his bike. ( Supplied )

"Our people are locked up more and more than anyone else up there. Certainly a lot of those people, I'd say the great majority of those people locked up, haven't been involved in the death of a child," he said.

"When we look at our mob going to jail for the simple thing of not paying fines, yet someone can be involved in the death of a child and there's no sanction whatsoever... I just find that hard to comprehend and I think any reasonable person, doesn't matter where they come from or whether they're Aboriginal or not, would have difficulty comprehending that decision."

Mr Gooda said the considerations the judge applied for Alexander showing remorse and attending rehabilitation should be applied more widely to Aboriginal people.

He said jail should be seen as a last resort and the Government needed to invest in "prevention, not detention".

Jack's father Michael Page said the sentence was "devastating".

"[Alexander] hasn't got the full hit of it. He got a slap on the wrist is what he got," Mr Page said.

Attorney-General speaks to prosecutors about appeal

NT Attorney-General John Elferink told the ABC he could not order an appeal on Alexander's sentence.

"I spoke to the head of the Director of Public Prosecutions (DPP) today but it is beyond my reach as the Attorney-General to direct the DPP to do anything and particularly beyond my reach to ask the court to do anything of that nature," he said.

He said the DPP head was considering his comments and would make a decision on whether to appeal.

Mr Elferink said he understood some of the comments and public feelings about the sentence.

"I can imagine that a lot of people would be disappointed in that sentence."

But Mr Elferink said the "race debate" should be left out of the issue and said the overrepresentation of Aboriginal people in prisons was due to a "passive welfare" system.

He said he believed the NT justice system was working well and to the benefit of Territorians.