Matsepe-Casaburri, who had been communications minister with oversight of state-controlled telecommunications firm Telkom, since 1999, died in hospital, a family member told South African radio.
Matsepe-Casaburri had started to liberalise the telecommunications industry in Africa’s biggest economy, spearheading the part-privatisation of Telkom and the much-delayed launch of the country’s second fixed-line operator Neotel .
But she was criticised by investors for failing to do enough to encourage competition for Telkom, in which the government still holds almost 40 percent.
With the government as Telkom’s biggest shareholder, the new minister will have a say in how the company should replace lost revenue from the sale of its Vodacom mobile unit and on whether it should try to buy another mobile operator, or even succumb to any possible foreign takeover attempt.
Media reports had previously speculated Matsepe-Casaburri could be replaced after an April 22 election, which the ruling ANC is expected to win, by Pallo Jordan, minister of arts and culture.
Telkom shares closed at 107 rand on Monday.
No one at the communications ministry or the presidency could immediately be reached for comment.