JOHANNESBURG - Thousands of ANC delegates hunkered down on Sunday to choose their next leader in a vote widely seen as a decisive moment in the country's post-apartheid history.
With public support for the ANC falling sharply, the party could face a struggle to retain its grip on power in the 2019 general election after ruling since Nelson Mandela won the first multi-racial elections in 1994.
Delegates could vote for the new leader as early as Sunday, with the five-day conference due to end on Wednesday.
President Jacob Zuma, whose reign has been marred by graft scandals, will step down as ANC chief at the meeting, but he will remain as head of state ahead of general elections in 2019.
He used his conference speech on Saturday to appeal for unity in a party riven by bitter factions under his rule.
He blamed the decline in the ANC's popularity on "perceptions in society that we are soft on corruption, self-serving and arrogant".
"Petty squabbling that takes us nowhere needs to take a back seat," he said.
"Our people are frustrated when we spend more time fighting among ourselves instead of solving the daily challenges they experience."
The ANC candidates had agreed "to abide by the outcome of the conference. I want each of them to bear that in mind," he added.
- Party split? -
Zuma's speech was greeted with weak applause and a partial standing ovation after raucous party delegates had danced and sang songs in support of their chosen candidate to succeed him.
Some analysts say the party could split after the contentious leadership battle.
The ANC is still South Africa's biggest party by far, but the 54 percent it won in local elections last year was its worst poll result since 1994.
Opposition parties the Democratic Alliance and Economic Freedom Fighters are hoping to exploit the ANC's woes in the 2019 election, with one possible outcome being a coalition government.
The conference, held outside Johannesburg, started seven hours late on Saturday after disputes over which delegates are qualified to vote.
Ben Payton, an analyst at the global risk consultancy Verisk Maplecroft, said Cyril Ramaphosa was well-positioned for victory but Nkosazana Dlamini-Zuma "remains within touching distance of an upset win".
"The conference provides an opportunity for the party to change direction after eight years in which the economy has flatlined, increasingly extreme rhetoric has scared off investors, and corruption has overwhelmed public finances," he said.