The State Government has revealed the projected impact of tough new burglary laws on already crammed prisons - 266 more inmates over four years.
But there is no money in the Budget for the $93 million needed to incarcerate them, prompting the Opposition to accuse the Government of wilfully ignoring a looming fiscal iceberg.
The revelation at Budget estimates yesterday came as Corrective Services Minister Joe Francis admitted "human error" allowed the escape of a convicted armed robber from Serco guards in Shenton Park on Wednesday.
Tough laws setting beefed-up mandatory minimum jail terms for violent and sexual assaults committed during home invasions, now before Parliament, are designed to send more people to jail for longer.
Mr Francis declined several times to release the projected impact of the laws on the prison population, saying potential savings through the deterrent effect of the laws had not been factored in.
Corrective Services Commissioner James McMahon revealed his department was preparing for the possibility of an extra 206 adults and 60 juveniles in jail after the legislation's first four years.
He said prisoner numbers were already growing faster than expected. The average daily prison population was expected to reach 4973 last year but as of yesterday, there were 5212 inmates. "The budget I was supposed to stick to in 2012-13 was $828 million but budget actual is likely to be $854 million - a $26 million increase," Mr McMahon said.
"That $26 million is a 3.1 per cent (budget increase) but the prisoner population has grown at 6 per cent. Does it concern me? Absolutely."
Mr McMahon hopes plans to reduce recidivism 5 to 6 per cent a year will mean the burglary law projections will not be realised.
Shadow corrective services minister Paul Papalia said it was "not good enough that we have such a significant gap in the Budget".
Mr Francis said the $93 million figure was a worst case scenario and "I'm not going to budget for absolute maximums".
He confirmed that Serco guards' failure to keep inmate Darren Goldsworthy handcuffed to themselves or an immovable object during a medical visit was a lapse in protocol.