PM rules out country wide royal commission

A royal commission into the detention of young people will be limited to the Northern Territory, Prime Minister Malcolm Turnbull insists.

Despite calls for the inquiry to be wider, he says royal commissions are most effective when their terms of reference are clear and focused.

"Royal commissions with sweeping terms of reference that go on for years and years often lose their way," he told Cairns 4CA radio on Wednesday.

Mr Turnbull will discuss the terms of reference with colleagues at a cabinet meeting on Thursday.

He hopes a directions hearing will be held in August ahead of hearings in September, October and November, with a report likely in early 2017.

He agreed with acting Labor leader Tanya Plibersek, who said all politicians should share responsibility for the treatment of young people in detention.

"There is no doubt that some of the mistreatment has occurred in the territory under Labor governments," Mr Turnbull said.

His decision to hold a royal commission follows an investigation by the ABC Four Corners program.