The head of the South African Truth Commission, Archbishop Desmond Tutu, has told a court that the murders of black activists during the apartheid era were part of state policy and couldn't just be blamed on what he called bad apples.

He was testifiying at the trial of the former South African President, PW Botha, who's charged with contempt for refusing to appear before the Truth and Reconciliation Commission.

Archbishop Tutu said the killings and other human rights abuses had been ordered from the top and were not simply the work of rogue elements within the security forces -- as Mr Botha's defence lawyer had argued.