DA spokesperson Ian Davidson told a media briefing in parliament on Thursday that early indications showed that the economy under a Zuma government would feature an end to privatisation and increased intervention.
He said such policies had no place in a modern enterprise-driven economy.
"While Zuma has gone to great lengths to assure business and potential investors that there will be no significant shift in economic policy under the new ANC leadership, it is becoming clear that economic policy continuity is not a foregone conclusion should he become South Africa's next president," he said.
Davidson said Zuma's policies would most likely hurt the very constituency that Zuma purported to represent.
He said since Zuma had ousted Thabo Mbeki from the presidency of the ANC, global investors had become sceptical about the country's future.
Davidson also expressed concern about the role Cosatu and the SA Communist Party played in securing Zuma's accession to the presidency of the ANC.
He said it was possible that the two organisations could demand a bigger say in policy formulation as a payment for its political support for him.