Alleged human rights violations in Australia and the treatment of prisoners will soon be scrutinised by the United Nations in a landmark visit.

The UN subcommittee on prevention of torture has announced it would visit six countries, including Australia and Nauru, to conduct random inspections in prisons, youth detention centres even aged care facilities.

The visit comes in the wake of the case of an intellectually impaired Indigenous boy who was kept naked in a Brisbane watch house.

Another, a teenage Indigenous boy who had both a neurodevelopmental disability and foetal alcohol spectrum disorder, had been stripped naked when he refused to wear an anti-suicide smock.

Subcommittee on Prevention of Torture (SPT) chair Sir Malcolm Evans said it was these incidents that would be placed under the microscope.

"Clearly things like that absolutely should not be happening but regretfully they do," Sir Malcolm said.

"We are not here to investigate individual allegations that people have made but that is precisely the sort of thing that, by our work … we should try to ensure cannot happen."

The Federal Government ratified the optional protocol to the convention against torture in December 2017, which was designed to prevent the mistreatment of people in detention, through inspection processes.

Sir Evans' committee would be visiting six countries to investigate the treatment of prisoners. ( Supplied: University College London )

It is the first time Australia will be subject to the UN inspections, with the investigators given unlimited access at random to any facility in the country.

Without notice the group can speak to any individual, at any hour of the day, see any part of the facility and access all documentation.

By the same token, Australia will only be given three to four months' notice before the investigators' visit.

"We always try to ensure we visit newly joining countries as soon as we possibly can ... to get to know what the issues in those countries are," Sir Malcolm said.

"We never say which places of detention we are going to go to in advance, we simply turn up.

"Our mandate extends to prisons, police stations, psychiatric hospitals where persons may be detained and not free to leave, social care institutions, immigration detention.

"The protocol is very clear on this and I have no reasons to suppose that Australia will not fully respect our mandate."

The subcommittee announced it would also tour Croatia, Lebanon, Madagascar and Paraguay.