Archbishop Tutu chaired the Truth and Reconciliation Commission

Officials said this week that up to 20 suspects who had not sought amnesty under the Truth and Reconciliation Commission (TRC) could face charges.

Perpetrators will be able to escape prosecution by naming their superiors who ordered the crimes.

The Khulumani Support Group said such plea bargaining would absolve those who had previously refused to confess.

"This is a perpetrator-friendly process to provide them with opportunities to now come forward to say: 'I want to come clean,'" said Marjorie Jobson, chairwoman of Khulumani, which represents 44,000 victims.

"But we believe that there were ample, very generous opportunities. Victims have never been vindictive. They have only asked for full disclosure and people didn't take those opportunities for several years," Ms Jobson told the BBC's Focus on Africa programme.

Legal mechanisms

National Prosecutions Authority spokesman Vusi Pikoli insisted that the planned prosecutions would not involve a second amnesty process.

"This is invoking existing legal mechanisms that we hope will lay this matter to rest so that we close this chapter of our history," he said.

Mr 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 TRC, which was set up to investigate apartheid-era abuses.

The TRC offered perpetrators the opportunity of amnesty in exchange for confession.

According to victims' groups, only 293 amnesty applications from former security agents were received before the TRC concluded its work in 1998, leaving many open to prosecution.

Mr Pikoli said 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

Corporations sued

In another development, arguments began in a New York court on Tuesday in a case brought by Khulumani against international corporations that did business in South Africa during the apartheid era.

Khulumani is claiming reparations on behalf of 87 South African victims from 23 corporations charged with aiding and abetting the apartheid regime.

"The story of economic development of this country (South Africa) is intimately bound up with foreign capital, technology and expertise," the appellant's court papers stated.

Failure to testify

The TRC 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 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.