Archbishop Tutu chaired the Truth and Reconciliation Commission

The head of the National Prosecuting Authority, Vusi Pikoli, said the cases involved gross human rights violations, including torture and killings.

He would not identify those targeted in the cases, which date from before the end of white-minority rule in 1994.

They focus on those denied amnesty or those who failed to appear before the Truth and Reconciliation Commission.

Mr Pikoli told a news conference that the authorities were currently prepared to prosecute in five of the cases, while 15 others required further investigation.

"Applicants who did not receive amnesty are clearly in our sights," he told reporters

"This is an opportunity to prosecute crimes of apartheid."

Failure to testify

The TRC was set up to probe human rights violations under apartheid. It heard the testimony of some 21,000 victims and perpetrators during its eight years of hearings.

Some 1,200 perpetrators were granted amnesty and 5,500 other applications were rejected.

A number of key figures, including the former South African president, PW Botha, refused to appear before the commission, prompting the families of victims and others to put pressure on the government to pursue the cases.

Last month, Archbishop Desmond Tutu said that South Africa should have prosecuted all perpetrators of apartheid-era atrocities who did not seek amnesty.

He was interviewed to mark the 10th anniversary of the foundation of the TRC.