US car giant General Motors (GM) has agreed to pay a symbolic sum of up to $1.5-million to victims of South Africa's Apartheid-era government, who are suing it and another four companies for helping prop up the white-minority State.

South Africa's Khulumani Support Group lodged a US class action lawsuit a decade ago against more than 20 firms it accused of aiding and abetting human rights violations, including torture and extrajudicial killings, under Apartheid.

Only five companies – General Motors, which has since filed for bankruptcy, Ford, Daimler, German defence group Rheinmetall and computer giant IBM – still stand accused.

"GM want to carry on with their business in South Africa and want to settle their scores and maintain good relations with the country's people," said Khulumani member Shirley Gunn, who was detained and tortured under white-minority rule that ended in 1994.

"But we are very grateful and can seriously start to redress the legacy of Apartheid."

GM said the settlement was agreed by a trust set up after the company declared bankruptcy in 2009, and as such would be a lot less than $1.5-million.

The company also said the settlememt contained no admission of wrong-doing and stressed it had "adamantly opposed" Apartheid.

However, Khulumani laywer Charles Abrahams said the payment to more than 20 Khulumani claimants should help their case against the remaining four companies.

"The fact that GM has made a without-prejudice offer to our clients clearly indicates that they acknowledge liability of some sort," Abrahams told Reuters.

"For us that is a significant step in corporate accountability and we hope it will stand us in good stead with our class action against Ford, Daimler, Rheinmetall and IBM."

A number of US Supreme Court justices have expressed scepticism over whether companies can be sued in the United States for alleged complicity in human rights abuses abroad.