Mamphela Ramphele.

Johannesburg - Respected anti-apartheid activist Mamphela Ramphele resigned as chairwoman of Gold Fields on Tuesday, intensifying speculation she is about to launch a political party to challenge the ANC.

Gold Fields said Ramphele had decided to retire “to further her socio-economic and political work”.

Former South African Airways chairwoman Cheryl Carolus will succeed Ramphele as chair, the company said.

Ramphele has been in the news in the past weeks for reportedly planning to set up a new political party.

She has declined to confirm or deny rumours in this regard.

Ramphele is scheduled to brief the media on Monday on her "political plans". - Reuters, Sapa