Men charged with alleged prison rapes were allowed to stay in shared cells – against strict protocols – by Queensland corrections staff who mistakenly believed their cases were “closed” and that they posed no risk, a report by the state’s ombudsman has found.

The ombudsman’s inspection report of the Brisbane correctional centre raises a number of concerns about the facility, including extensive overcrowding, health facilities that are not fit for purpose and complaints that chicken served to detainees and staff is often undercooked.

Cells at the prison are primarily designed for single occupancy. Under inspection “standards”, prisoners are to be accommodated solo in cells unless they request to be placed with a cellmate.

But the ombudsman found the Brisbane facility was operating at 168% of its design capacity, meaning that most often people in custody are “doubled” up in cells.

The report revealed concerns about how prisons across Queensland were documenting and responding to allegations of sexual assault, in particular when deciding whether to place people in single- or double-occupancy cells.

The inspection found that “circumstances where prisoners who were vulnerable or who had previously experienced or alleged sexual assault by a cellmate were sharing a cell”.

It also “identified three incidents where a prisoner was sharing a cell after they were alleged to have sexually assaulted their cellmate”.

In one case, a prisoner was transferred to another correctional centre while under investigation for alleged sexual assault. He was later charged with the alleged rape of a former cellmate, and details of the charge were added to his case notes.

But the following day, staff added another case note – a “cell sharing review” – that found there were “no apparent identified risks or factors that would prevent shared cell accommodation”.

Corrections staff told the ombudsman that workers at the other correctional centre had “incorrectly” assumed the matter had been finalised, when an internal investigation was “closed”. The investigation in this case had been closed only because the matter was referred to police.

In its response to the ombudsman, Queensland Corrective Services said the second prison had conducted an internal review of similar cases “and found further instances where the same error had been made by staff”.

Staff and prisoners at Brisbane correctional centre also told the ombudsman they had become sick after being served undercooked chicken from the prison kitchen.

Inspectors noted they “observed undercooked chicken wings, which were visibly bloody and being served to staff and visitors”.

“In the kitchen, we saw the chicken being stacked on multiple trays and cooked using steam‑assisted commercial ovens. We noted that the chicken in the middle of the trays was lighter in colour than the chicken around the edges, and there does not appear to be a consistent process for checking that food in the centre of the racks is adequately cooked.”

The report noted that healthcare facilities at the prison were “not fit for purpose” and that there were extensive wait lists for prisoners to receive treatment.

The ombudsman said it had raised issues about healthcare with senior management at the centre, who “agreed that the infrastructure within the medical centre is not conducive to contemporary healthcare provision. They said they are restricted at a centre level as to what can be changed.”

The ombudsman recommended that a new medical centre be built for the prison but the idea was not accepted by Queensland Corrective Services.

In its response to the report, the department said it regularly reviewed “health service infrastructure capacity in all correctional facilities”.