Prison officers have been cleared of using excessive force against a 41-year-old Western Australian Aboriginal inmate who was taken to hospital in a critical condition, rejecting reports she had been "body slammed" by a guard.
The Department of Justice says the Bandyup Women's Prison inmate had been found trying to access a vending machine and was ushered back to her cell on the weekend, then hospitalised the following day.
An investigation by the department's Professional Standards Division has found no evidence she was subjected to excessive or unnecessary force by anyone.
"Based on the accounts of witnesses present during events last weekend, investigators concluded the prisoner's need for urgent medical treatment arose from pre-existing conditions," the department said on Thursday.
"There was no medical evidence of trauma or injury and investigators were unable to substantiate a claim the prisoner had been 'body slammed' as reported by media."
Corrective Services Commissioner Tony Hassall said he was satisfied the prisoner received timely medical attention when her cell mate pushed the duress alarm.
The prisoner remains in hospital in a stable condition.