Former deputy president Jacob Zuma's friends and family have urged police to investigate what they describe as the "strange and mysterious" death in a car accident of the Gauteng chairperson of the Friends of Jacob Zuma Trust Fund.

But police said they could not confirm or deny that former South African ambassador to the United Nations George Nene had been involved in a fatal accident on Saturday night, or that any investigation into Nene's death was taking place.

While hesitant to directly suggest who might be behind the 59-year-old father-of-four's death, Friends of Jacob Zuma Trust Fund spokesperson Kaizer Mohau said it was "very coincidental" that Nene had died in an accident days after Zuma had "mentioned him by name at an event on the East Rand" and after he had "worked very hard to mobilise support" for Zuma.

Three members of Zuma's clan, Silas Zuma, Margeret Zuma and the Reverend Albert Zuma, also expressed sadness over Nene's death, before telling a Trust Fund press conference that they were convinced that Zuma was innocent of charges brought against him.

Zuma, 63, will appear in the Johannesburg High Court on Monday, where a total of 23 witnesses will testify about the rape allegations against him. The complainant, a 31-year-old HIV and Aids activist, has alleged that Zuma raped her after she had been invited to sleep over at his Forest Town mansion.

With acknowledgements to Karyn Maughan and The Mercury.