NT inquiries 'a substitute for action'

The sheer volume of inquiries into the Northern Territory's juvenile justice system is evidence of a "persistent failure", the royal commission into youth detention has heard.

The inquiry being led by co-commissioners Margaret White and Mick Gooda sat in Darwin's Supreme Court on Tuesday and heard there's been a national inquiry, four NT government reviews and 23 independent reviews relevant to youth detention.

Senior counsel assisting the commission Peter Callaghan SC questioned whether all the previous probes and their recommendations have been effective.

"Do we need to confront some of the inquiry mentality in which investigation is allowed as a substitution for action and reporting is accepted as a replacement for results?," he said.

"The bare fact that there has been so much said and so much written over such a long time is suggestive of a persistent failure that should not be allowed to endure."

Prime Minister Malcolm Turnbull announced the probe after shocking footage of boys being tear gassed at the Don Dale Youth Detention Centre was aired on national television earlier this year.