In what human rights groups have labelled an "international embarrassment", the United Nations torture prevention body has taken the "drastic" step of suspending its visit to Australia, saying the country was in clear breach of its obligations.
The federal government has said it "regrets" the decision by the UN Subcommittee on Prevention of Torture (SPT).
The SPT on Sunday said it had been "obstructed" and prevented from visiting several sites where people are detained.
In a statement, they said the visit "had been compromised to such an extent that they had no other option but to suspend it".
"This is not a decision that the SPT has taken lightly," delegation head Aisha Shujune Muhammad said.
"This is a clear breach by Australia of its obligations under OPCAT.
"It is deeply regrettable that the limited understanding of the SPT's mandate and the lack of co-operation stemming from internal disagreements, especially with respect to the states of Queensland and New South Wales, has compelled us to take this drastic measure."
Australia ratified the Optional Protocol to the Convention against Torture and other Cruel, Inhuman or Degrading Treatment or Punishment (OPCAT) in 2017 under Malcolm Turnbull's coalition government.
Last week Attorney-General Mark Dreyfus welcomed the visit and thanked the state and territory governments — with the notable exception of NSW — "for their cooperative approach to facilitating visits by the delegation".
The UN delegation did carry out visits to several facilities last week, including to the Don Dale Youth Justice Centre in Darwin.
Tasmania allowed the committee to enter six custodial sites, including the Ashley Youth Detention Centre which is under scrutiny by a state-based Commission of Inquiry.
The inquiry has heard disturbing evidence of rape, assaults and staff abuse at the centre which has been earmarked for closure.
Why surprise visits?
A Corrective Services NSW spokesperson said the UN representatives were "refused entry without incident" to the Mary Wade Correctional Centre and the Metropolitan Remand and Reception Centre Sydney on Sunday and the Queanbeyan Court Cells last Tuesday "as they did not have prior approval".
"Any person who seeks to visit a correctional site operated by or on behalf of CSNSW must have prior written authorisation or will be refused entry," the spokesperson said.
"This includes visits by foreign officials including the United Nations Subcommittee on the Prevention of Torture."
Amnesty International said the SPT had been invited by Australia and that the visits are meant to be unannounced by design, but occur within a known two-week window.
Steven Caruana, coordinator of the Australia OPCAT Network, said the point of unannounced visits was to provide a "distortion-free" picture "to help ascertain the real situation of persons deprived of their liberty".
"Additionally, the possibility of being subjected to unannounced visits can have an important deterrent effect in and of itself," he said.
Queensland Corrective Services has also been contacted for comment.
NSW Corrections Minister Geoff Lee last week told radio station 2GB that the Queanbeyan facility was right to turn the SPT away.
"The whole role of our jail system is to keep people safe, protect us from the criminals that we lock up every day. It's not to allow people just to wander through at their leisure," he said.
"They should be off to Iran looking for human rights violations there."
In a statement, Mr Dreyfus said it was a "disappointing" result.
"It is disappointing that the New South Wales government refused to allow the SPT to visit any state-run places of detention across that state," he said.
He said there were difficulties getting access to some places in jurisdictions other than NSW, but that attempts were made to resolve those issues in good faith.
"The decision of the SPT to cancel its visit, more than halfway through its scheduled time in Australia, is a development that could have been avoided," he said.
"It is vital that places of detention in Australia maintain the rights of those who are held within their walls.
"Australia does not resile from efforts to raise global human rights standards and hold others to account. Likewise, we remain willing to face scrutiny of our own human rights record."
'Embarrassing debacle' undermines trust
Mr Caruana said the SPT had only suspended visits three time in the past — in Rwanda, Ukraine and Azerbaijan.
He said the suspension "undermines trust in Australia".
"It made a commitment to the rest of the world that it could be trusted as a leader on human rights. The SPT visit was the true test of that promise and we've failed," he said.
"There can really be no excuse as to why the delegation was hindered. Australia has had almost five years to prepare for this visit.
"Australia will now have to answer for this embarrassing debacle."
Sophie McNeill, Australia researcher at Human Rights Watch, said it "sends an appalling message to the region".
"We work with a whole range of governments, some of them really in authoritarian [countries], to try and encourage them to cooperate with the UN and the importance of these kinds of UN bodies and treaties," she said.
"And here we are in Australia, not upholding our international obligations. It's deeply embarrassing."
She said she hoped Mr Dreyfus could obtain guarantees from states to ensure inspectors have access and their visit could resume as soon as possible.
Amnesty International Australia impact director Tim O'Connor said if states and territories were complying with their OPCAT obligations, "then they have nothing whatsoever to fear".
"Preventing the SPT from doing its job raises grave concerns about the conditions of people in detention in Australia," he said.
"This is an international embarrassment and shows how paper-thin the commitment to Optional Protocol to the Convention Against Torture is.
"We need only look at the horrific experiences of young people in youth detention, allegations of systemic abuse, the continued use of tools of torture like spit hoods and the hundreds of First Nations people who have died in custody to see that there are serious problems that require independent scrutiny."
Ms McNeill added all countries have issues with their detention systems, and there were some "alarming issues" in Australia, including Don Dale and the treatment of children in the Northern Territory, Banskia Hill in Western Australia, and people held in solitary confinement.
"All prisons in Australia aren't transparent enough, and they're not used to this level of scrutiny," she said.
"But they're going to have to be, because we've signed this agreement, and we have to uphold our international obligations."
