Corrective Services Minister Joe Francis said yesterday it would be "reckless and irresponsible" to cancel Serco's court security and custodial services contract, which has been breached through several escapes in recent months.
Responding to Labor's policy of returning the responsibilities to the Department of Corrective Services, Mr Francis said a "public sector comparator" test showed it was 22 per cent cheaper for a private operator to do the job.
Mr Francis said private companies had a more flexible workforce, were more empowered to punish staff for failures and less blighted by workers' compensation claims than public sector employers.
He said no guard, regardless of their employer, could have predicted a toilet handrail that Bradley McIntosh-Narrier allegedly brandished during his escape from Joondalup Health Campus last week had not been secured properly to the wall.
"You can't cancel Serco's contract for that," he said.
"That's a ridiculous proposition which would cost taxpayers tens of millions of dollars over years and is just Labor caving in to the union movement."
Serco's five-year, $476 million court security and custodial services contract was struck in June 2011.
Shadow corrective services minister Paul Papalia said if elected in 2017, Labor would break any contract for privatised court security and custodial services provided severance penalties weren't "tens of millions of dollars".
"In this case our overriding principle is whether it's a good service and I don't think it is," he said. "My main argument is over transparency. When things go wrong in the public sector you know about it."
Mr Papalia queried the accuracy of the public sector comparator for the contract because it did not account for costs such as extra "hospital sits" and separately billed prisoner transport to funerals.
He said he regretted that Labor did not take court security and custodial services from the private sector in 2007.
Inspector of Custodial Services Neil Morgan this week told ABC Radio the debate should move on from public versus private components of the prison system that were "here to stay".