JOHANNESBURG (Reuters) - The African National Congress (ANC), South Africa’s ruler since the end of apartheid, faces perhaps the most pivotal few days in its recent history when it meets over the weekend to choose a successor to Jacob Zuma as party leader.

The ANC’s electoral dominance means whoever wins the job is likely to become South Africa’s next president.

But Zuma’s presidency, tainted by corruption and scandal, has badly tarnished the ANC’s image both at home and abroad. The party once led by Nelson Mandela is now deeply divided.

Investors will also be watching events closely.

Economic growth in Africa’s traditional powerhouse has been lethargic over the last six years and the jobless rate stands near record levels.

Political instability, including the questions over who will replace Zuma, has been cited by credit rating agencies as a big factor behind their decision to cut South Africa to “junk”.

The two frontrunners in the race are Deputy President Cyril Ramaphosa and Nkosazana Dlamini-Zuma, a former cabinet minister and ex-wife of the president, who is backing her.

Ramaphosa’s promises to fight corruption and revitalize the economy have gone down well with foreign investors and ANC members who think Zuma’s handling of the economy could cost the party dearly in the next national election set for 2019.

Dlamini-Zuma is associated with a radical brand of wealth redistribution which is popular with poorer ANC voters angry at racial inequality.

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Analysts say the outcome of the leadership contest is too close to call and that the bitterness of the power struggle between Ramaphosa and Dlamini-Zuma has increased the chances of the party splitting before the national election.

The Ramaphosa camp sees the faction aligned with Zuma and Dlamini-Zuma as having seized control of the ANC and betrayed the values of the anti-apartheid struggle which it led.

Dlamini-Zuma’s team thinks Ramaphosa would not be decisive enough in addressing the gaping racial inequalities that persist in South Africa - the core of her campaign.

Some analysts say Zuma’s influence over who succeeds him has been diminished by his travails.

The 75-year-old president has faced -- and denied -- numerous corruption allegations since taking office in 2009 and has survived several votes of no-confidence in parliament.

SPLITS IN ANC

The ANC expects to announce the winner early on Sunday, the second day of a five-day party conference which only takes place once every five years, ANC spokesman Zizi Kodwa said.

Party officials insist members will accept the outcome of the leadership vote and avoid a fallout.

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“We need to take out this item from the conference agenda as quickly as possible,” ANC spokesman Kodwa told radio station 702 on Friday.

Disillusioned ANC members have left to form new political groupings on several occasions -- the most recent example being the African Democratic Change party founded by former ANC lawmaker Makhosi Khoza this year.

In August, Zuma narrowly survived another attempt in parliament to force him from office after some members of his party voted with the opposition.

Enoch Godongwana, who chairs a party committee on economic policy, said there had been interactions between the main opposing party factions to prevent the party splintering.

“If the ANC collapses, do you have anything in its place which can hold this country together on a national basis? I would argue that at this stage in time you simply do not have a replacement for the ANC,” he told reporters on Thursday.

RICH MAN, POOR MAN

Ramaphosa, a former trade union leader who became one of South Africa’s richest people, is seen as more business-friendly than Dlamini-Zuma and the five other leadership contenders.

Ramaphosa edged Dlamini-Zuma by getting the majority of nominations to become leader of the party, but it is far from certain he will become the next leader and therefore the likely next president.

He is expected to be backed by ANC veterans, labor unions and civil society organizations.

“If Dlamini-Zuma wins, a split is very likely, because the Ramaphosa camp views itself as the ‘old ANC’. This is a last attempt by them to regain control of the party from the Zuma faction,” said Darias Jonker, director for Africa at Eurasia Group.

Political analyst Ralph Mathekga said he thought Dlamini-Zuma would win the leadership, partly because of her strong support in KwaZulu-Natal province, which is sending the most delegates to the conference.

As well as Zuma’s support, she also has the backing of the ANC’s influential women’s and youth leagues.

The rand rallied on Friday on signs that her bid for the ANC leadership was weakened by court cases which will obstruct some delegates who back her from attending the party conference in Johannesburg.

As well as electing a new leader, the ANC will choose senior officials such as the secretary general and members of the National Executive Committee. It will also set policy priorities for the leadup to the 2019 election.