Prisons should cut back on strip searches given they are finding hardly any contraband, the Ombudsman says.
In the four years to mid-2015, 430,000 strip searches yielded just 675 items: a hit rate of 0.15 percent.
The chief inspector of the Ombudsman's Crimes of Torture Act, Jacki Jones, said strip searching was highly invasive and should be restricted to when it was truly necessary.
Indiscriminate use of CCTV surveillance in cells and strip search areas could constitute a serious privacy breach, she said.
The Department of Corrections could cut back without compromising the safety and security of staff and prisoners, Ms Jones said.
Corrections had said it had got the number of searches right and would not change.
Yesterday, human rights lawyer Michael Bott called on the Ombudsman to investigate what he said were routine strip searches designed to degrade prisoners.
He said Section 98 of the Corrections Act was clear that guards may strip search prisoners who were being moved around, but that it was discretionary.
"The Department of Corrections is breaking the law, it's not acting in accordance with the act, it's a discretion, an officer 'may'," he said.
"Since when in the English dictionary does the word 'may' mean 'must'? It does become degrading because what they're doing is, without cause, they're making prisoners take their clothes off, squat, lift up their genitals, their breasts, parting their buttocks etcetera," he said.