This would result in the release of about 9,000 prisoners from next week, Correctional Services Minister in Mandela's Cabinet Sipo Mzimela said here, according to the Sapa news agency.

South Africa's prisons face a serious overcrowding problem -- in February there were nearly 1,30,000 prisoners occupying 230 prisons built to cater to only 96,325 convicts.

The South African Government is looking into the possibility of setting up floating prisons and converting a 54-storey apartment block in central Johannesburg into a correctional service facility.

Mzimela was recently forced to abandon the idea of renovating old mine shafts to make way for detention centres after protests from human rights groups. Mandela turns 80 today amid year long birthday celebrations that have plunged South Africa into "Madibamania" -- a respectful reference to Mandela's clan name. In his 80 years, Mandela spent 27 years in jail and took on apartheid's evil empire, defeating it with the implacable dignity and reconciliatory attitude that have become his hallmark. Mandela, who endured his time in prison only to suffer the loneliness of a broken heart, won the adulation of millions of people around the world for his role in defeating South Africa's system of racist oppression.

He was among the first to advocate armed resistance to apartheid in 1960, but was quick to preach reconciliation and forgiveness when the country's white minority rulers began easing their grip on power 30 years later.

"I have cherished the ideal of a democratic and free society in which all persons live together in harmony and with equal opportunities," Mandela said in one of his most famous speeches, delivered to the court that found him guilty of trying to overthrow the apartheid Government in 1964 -- a capital offence. "It is an ideal I hope to livefor and to achieve. But if needs be, it is an ideal for which I am prepared to die," he said.