Cyril Ramaphosa, the new leader of South Africa's governing ANC party, said on Thursday he aims to stamp out corruption and pursue a policy of "radical economic transformation" that will speed up expropriation of land without compensation.

Ramaphosa, a 65-year-old union leader who became a businessman and is now one of South Africa's richest people, is likely to become the country's next president after elections in 2019, because of his party's electoral dominance.

His promise to fight rampant corruption and revitalise the economy has been hailed by foreign investors.

"This conference has resolved that corruption must be fought with the same intensity and purpose that we fight poverty, unemployment and inequality," Ramaphosa said in his maiden speech at the close of a five-day party meeting where he was elected.

"We must also act fearlessly against alleged corruption and abuse of office within our ranks," he said in the early hours of Thursday after a long delay.

Ramaphosa, who is South Africa's deputy president, was elected the new leader of the African National Congress (ANC) on Monday, succeeding President Jacob Zuma as party head after Zuma's presidency became tainted with corruption allegations.

Ramaphosa's narrow victory over former cabinet minister and African Union Commission chairwoman Nkosazana Dlamini-Zuma, 68, is seen as a pivotal moment for the ANC, which launched black-majority rule under Nelson Mandela's leadership 23 years ago but is now deeply divided with its image tarnished.

Ramaphosa paid tribute to Zuma in his speech, saying the ANC would be "united" despite a fractious campaign. Zuma had backed his ex-wife Dlamini-Zuma for ANC's top job.

However, investors are concerned that Ramaphosa may not be able to push through policy changes because the ANC's top decision-making group, known as the "Top Six", was split down the middle, with three politicians apiece drawn from Ramaphosa's camp and that of Dlamini-Zuma.

Analysts warned that the division of the party presidency, held by Ramaphosa, and the state presidency in Zuma's hands, could lead to policy uncertainty or paralysis.

"Mr Zuma, for instance, still occupies South Africa’s presidency – a cohabitation that may cause a period of policy uncertainty," Capital Economics Africa economist John Ashbourne said in a note.

Expectations that Ramaphosa would win the ANC race had pushed the rand to 12.5200 per dollar on Monday, its firmest since March 27, when a cabinet reshuffle by Zuma rocked markets and triggered credit ratings downgrades to "junk."

The rand weakened on Tuesday, but firmed on Wednesday as investors continued to digest how much clout Ramaphosa wields.

"Victory for Ramaphosa, but not a loss for Zuma," said Geoff Blount, managing director at BayHill Capital.

South Africa, the continent's traditional powerhouse, has had lethargic growth over the last six years and the jobless rate stands near record levels.

Ramaphosa also had a warning for corporate executives.

"We must investigate without fear or favour the so-called 'accounting irregularities' that cause turmoil in the markets and wipe billions off the investments of ordinary South Africans," he said.

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