Queensland will change its laws so United Nations inspectors can check in on patients being detained at mental health facilities, the premier says.

A UN Subcommittee on Prevention of Torture on Monday suspended a tour of Australia's detention facilities, saying Queensland and NSW hadn't cooperated.

The inspectors were checking if Australia was fulfilling its obligations under the UN's Optional Protocol to the Convention against Torture (OPCAT), which it has signed.

The Queensland government insisted that it did cooperate with the delegation, giving them "unrestricted access" to a Brisbane correctional centre, where they had the opportunity to meet prisoners and staff, on Saturday.

However, Queensland Health says it was legally prevented from giving the UN inspectors physical access to some detained patients living with severe mental illness or cognitive impairments.

Premier Annastacia Palaszczuk says proposed laws to allow the delegation to visit those patients in person will be tabled by the end of this year.

"There were some restrictions around physical access to authorised mental health facilities and the Forensic Disability Service," she told parliament on Wednesday, in response to a question from Greens MP Michael Berkman.

"Advice was also provided about how to support the Subcommittee visit within the existing legislation.

"In August this year, our government passed legislation to establish an Independent spectrum detention service, which will provide greater oversight of Queensland's detention facilities.

"An OPCAT bill will be introduced by the end of the year to address the current legislative barriers that restrict physical access."

Mr Berkman said the government's claims that access to some patients couldn't be granted was an excuse, and it had had five years to remove any legal barriers.

"Qld also just passed a Bill for an inspectorate of detention services that is NOT consistent with our OPCAT obligations," the Greens MP tweeted.

"The Greens will be looking closely at this upcoming Bill to see if it's any better, or if we'll continue embarrassing ourselves on the international stage."

On Monday, federal Attorney-General Mark Dreyfus said he was disappointed in NSW for refusing access, and regretted the UN's avoidable exit, but it would not change Australia's commitment to the anti-torture treaty.

Corrective Services NSW commissioner Kevin Corcoran said a recent Inspector of Custodial Services report had listed five facilities housing hundreds of inmates as inadequate.

"We've got our own standards ... they don't meet those standards," he told a budget estimates hearing on Monday.

Assistant commissioner Leon Taylor said some infrastructure dated back to the Victorian era and did not support "contemporary correctional practice".

Legal experts and academics, and prisoner advocacy groups condemned NSW and Queensland for blocking access.