Human error was behind yesterday's prisoner escape from Serco guards at Shenton Park, Corrective Services Minister Joe Francis has confirmed.
Twenty-two-year-old convicted armed robber Darren Goldsworthy was able to outrun guards during a routine medical visit to Royal Perth Hospital's Shenton Park annexe about 1pm despite being handcuffed.
He was arrested about an hour later.
After a separate escape from Joondalup Hospital in December, the Department of Corrective Services introduced enhanced protocols requiring prisoners to be handcuffed to a prison guard or immovable object at all times.
During Budget estimates this morning, Mr Francis said this had not occurred during the Goldsworthy transfer.
"My understanding is that process wasn't followed yesterday, which is where human error comes into it," he said.
Serco holds DCS's custodial services and court security contract but is under pressure after a rash of escapes from custody in recent months.
Two escapes in a year is enough to trigger a cancellation clause.
Shadow corrective services minister Paul Papalia this morning said there had been four escapes in four months and asked how many needed to occur before Mr Francis would consider cancelling the contract.
Mr Francis said escapes due to human error were no more likely to occur when the guard at fault was wearing a Serco uniform than any other.
Pressed by Mr Papalia, Mr Francis declined to commit to releasing the report into yesterday's escape.
"Are we to just take you at your word about any potential flaws in the contract that led to the escape," Mr Papalia asked.
Mr Francis said he did not want to reveal information that could incite further escape attempts and said the public should have absolute faith in the integrity of DCS Commissioner James McMahon.
Mr McMahon told the hearing the CS and CS contract was currently subject to a routine mid term review into its effectiveness by the Department of Finance.
"All options regarding that review are on the table," he said.