Jacob Zuma shows his delight after hearing that he's been elected president of the African National Congress. (Jerome Delay, AP)

Polokwane - Left-wing populist Jacob Zuma has won the leadership of the ruling ANC, lining him up for the presidency of the country but creating deep uncertainty about his policies.

The African National Congress dominates South African politics, so Zuma is almost certain to become head of state when his ousted ANC rival, Thabo Mbeki, has to step down as president in 2009.

Zuma's win on Tuesday raises the question of whether Mbeki will become a lame-duck president, paralysing decision-making because the country's two most powerful posts will be split between rivals once united in the fight against apartheid.

Corruption charges

Adding to the uncertainty, Zuma could face revived corruption charges in an arms scandal, raising the possibility that he could be jailed before he succeeds to the presidency.

"We can anticipate this conflict extending over the next two years. It is going to be particularly precarious when Jacob Zuma gets charged, if he does get charged over the corruption scandal," said political analyst Adam Habib.

Senior ANC officials said Zuma's election was unlikely to lead to a shift in economic policy. "At the moment, there are no ideological differences ... The policy is in place and intact," said ANC deputy leader Kgalema Motlanthe.

Some analysts had raised concerns Zuma would tilt Africa's largest economy to the left, although he has tried to reassure investors. Mbeki took a pro-business stance and the economy has registered its longest period of growth in the past nine years.

Market reaction to Zuma's win was muted. The rand was about two cents firmer, trading at 6.8999 against the dollar two hours after the results were released.

Fears of a move to the left

"The focus now is going to be on learning about Zuma's vision for the country and his likely choices for close political and economic advisers," said Absa Capital's head of research, Jeff Gable.

Some investors were worried Zuma would tip policies towards those of his staunch supporters, the country's powerful trade unions and Communist Party, who have railed against Mbeki's pro-business stance.

Trade union federation Cosatu has called on the government to loosen monetary policy and increase spending to bring the benefits of an economic boom to millions of poor and unemployed.

But Motlanthe said the new ANC leadership would not be in debt to the unions. "There is no room for payback ... basic policy will not change," he said.

There are fears a leadership paralysis could delay action to deal with the country's Aids crisis, one of the world's worst crime rates and poverty that still blights the lives of millions of blacks more than a decade after the end of apartheid.

With acknowledgement to News24.