Speaking at a media briefing this week, Ramphele was quoted as saying: "There is no doubt that I will be asked at some stage, " the Saturday Star reported.
She could not comment further.
Gold Fields said this week it was being investigated by the United States Securities and Exchange Commission.
Mbete was allegedly a beneficiary in a 2010, R2.1-billion deal apparently linked to the granting of a mining licence for the company's South Deep mine near Johannesburg, the newspaper reported.
The ANC said it was considering legal action against the Mail & Guardian, which reported that Gold Fields buried a New York law firm's finding that a R25-million share allocation to Mbete constituted bribery.
Ramphele was the former chairperson of Goldfields. – Sapa