"Dr Ramphele has decided to retire as chair to further her socio-economic and political work," spokesman Sven Lunsche said in statement.

Businesswoman Mamphela Ramphele has resigned as Gold Fields chairwoman with immediate effect, the company said on Wednesday.

"Dr Ramphele has decided to retire as chair to further her socio-economic and political work," spokesman Sven Lunsche said in statement.

"She has resigned from most of her private sector directorships and will relinquish all other remaining private sector directorships and positions to focus on these activities."

He said non-executive director Cheryl Carolus would succeed Ramphele.

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".