Delegates at the ANC's national elective conference in Manguang in the Free State started voting for the party's top six officials around 12.30am on Tuesday.
The ANC conference nominated its preferred candidates for their leadership on Monday afternoon.
President Jacob Zuma and Deputy President Kgalema Motlanthe were both nominated to lead the ANC. Cyril Ramaphosa, Mathews Phosa and Tokyo Sexwale were nominated for deputy president.
Motlanthe withdrew his candidacy for deputy president.
Two candidates were nominated for secretary general – Gwede Mantashe and Fikile Mbalula. Mantashe currently holds the position.
Jessie Duarte was the only person standing for deputy secretary general.
Baleka Mbete and current deputy secretary general Thandi Modise were both standing for national chairperson.
Gauteng chairpersoon Paul Mashatile and KwaZulu-Natal chairperson Zweli Mkhize were nominated for treasurer general.
Electoral committee member and ANC veteran Andrew Mlangeni said the voting would take place by secret ballot.
The election process would be handled by the Elexions Agency, which was a technical team. Delegates tags would be scanned with a hand held scanner. This was linked to a computer that would capture the names of the delegates and mark that they had received a ballot paper. Each delegates' left thumb would be marked with indelible ink, in case of computer failure or a dispute.
A total of 200 booths had been set up for voting and votes would be counted manually.
Thobile Thomas from the Elexions Agency said 4 075 delegates were expected to vote. – Sapa