Ramaphosa was elected South African President Jacob Zuma's deputy in the African National Congress in December and said at the time he would consequently be reviewing his various business interests.

The former anti-apartheid mining union leader is one of Africa's richest men and sits on the boards of some of the continent's biggest companies.

His investment company, Shanduka Group, is a quarter-owned by China's sovereign wealth fund and has stakes in mobile phone giant MTN and Standard Bank, Africa's biggest bank by assets.

He also sits on the board of Standard Bank and brewer SAB Miller.

Ramaphosa is expected to become South Africa's deputy president after national elections in 2014, teeing him up as a possible head of state should the ANC win elections five years later.