It continued, "Since 2009, investigations have uncovered 1,529 persons in the criminal justice system who were possibly involved in corruption-related crime.

"For the year April to September 2011, 192 officials were criminally charged regarding corruption, resulting in 86 officials being convicted, while a further 296 officials were departmentally charged."

What are conditions like in South African jails?

South Africa's jails were put under the spotlight during the extradition hearing of Shrien Dewani, the Briton who stands accused of ordering a hitman to murder his new wife in 2010.

One of the defense's arguments -- not upheld -- against extradition was that Dewani would not be safe in South African custody.

His lawyer quoted figures from a South African report suggesting that almost half of prisoners believed sexual abuse was a feature of life in South African jails.

Nooshin Erfani-Ghadimi, project coordinator for the Johannesburg-based Wits Justice Project, told CNN that South Africa's constitution and its bill of rights with regards to prisoners' rights were among the best in the world.

However, she said, overcrowding meant "unfortunately that doesn't necessarily translate into practice."

"A legacy of apartheid is that prison cells are still unfortunately a place where prisoners can be abused," Erfani-Ghadimi said.

South African public broadcaster SABC cited the Correctional Services Department as saying prisoners with disabilities were treated with dignity and enjoyed the same rights as able-bodied inmates.

However, a "statement of agreed factual findings" in the case of inmate Dudley Lee -- who contracted tuberculosis while imprisoned -- may point to a different reality. Lee said he "begged, bullied and bribed" to get the medication he needed.