Bloemfontein - Witnesses summoned by the Hefer Commission of Inquiry may not refuse to testify or refuse to answer any question, commission secretary John Bacon says.

But they may ask not to be identified and to testify in camera.

The commission, headed by retired appeal judge president Joos Hefer, is investigating allegations that national director of public prosecutions Bulelani Ngcuka had been a spy for the apartheid government.

The Sowetan quoted journalist Ranjeni Munusamy earlier as saying she would refuse to testify.

She quit the Sunday Times after admitting she had passed documents to the City Press showing Ngcuka had been probed by the ANC.

With acknowledgements to Sapa and the Cape Times.