Public safety could be risked if a plan to cut about 70 positions at Mobilong Prison goes ahead, the secretary of the corrections officers' union says.
Public Service Association secretary Nev Kitchen said his organisation and the Department of Correctional Services had agreed to take the job cuts plan "back to the drawing table" at a meeting today, which followed a snap strike on Wednesday.
Prison staff from around South Australia launched a round of industrial action this week after learning of the proposal to reduce staff numbers at Mobilong by the equivalent of 39.1 full-time positions, or about a third of the prison's workforce.
The corrections department has been seeking to "improve the quality, effectiveness and efficiency of our prison system", according to its 2018-22 strategic plan, through the a program titled Better Prisons.
Mr Kitchen said such efficiencies would include reducing the number of staff in gate houses and kitchens.
But he argued that the department's business case, based on a comparison with staffing numbers at the privately operated Mount Gambier Prison and other private prisons interstate, was flawed.
"When you're trying to compare apples with apples, it's very different," he said.
"For all we know, G4S might be operating that operation at a loss ... in exchange for operating other places at a profit.
"Any comparison of the daily (dollar) figure to house an inmate at Mount Gambier with the daily figure to house an inmate at Mobilong is fraught with complexity unless you know the data, and you never know because it's commercial in confidence.
"With interstate (private) prisons, the same applies."
In a statement, Corrections Minister Corey Wingard said the government's quest for efficiency in the prison system was something people, including employees, should be excited about.
"Benchmarking takes the best aspects from other correctional systems and investigates whether our jails can use them," he said.
"Anyone who has a job in the public prison system will keep one if they so choose.
"The court has ruled the Department of Corrections has fulfilled consultation requirements to the union - it's time they got on board with helping the government build a better prison system."
Negotiations are likely to continue for a number of months.
Mr Kitchen said public safety would remain paramount to the PSA during those talks, as would the safety of prison staff: "if they're injured, they can't protect the public".
In the meantime, the SA Employment Tribunal has ordered corrections officers not to strike again until at least August 7.