"We were behaving like a rather tatty political party," Kader Asmal, an outgoing national executive committee member, said.
"For many of us it was a shock. The undertones are about power, let's be frank about that."
The extent of division became clear on Tuesday night when five of Zuma's allies swept aside Mbeki's supporters in the party's most senior positions.
William Gumede, Mbeki's biographer, said reuniting the ANC and satisfying his disparate group of supporters would be Zuma's key challenges.
"The ragbag collection of groups that back Zuma ranges from socialists and trade unionists to supporters of virginity testing and the death penalty," he wrote in the Guardian newspaper.
"Dashed expectations may be the catalyst for a break-up of the ANC."
|"Dashed expectations may be the catalyst for a break-up of the ANC" |
William Gumede, Mbeki's biographer
Zuma's win now raises the question of whether Mbeki will become a lame-duck president, as South Africa's two most powerful posts will now be split between rivals in one party.
Al Jazeera's Mike Hanna said that the ANC was experiencing greater divisions than ever before.
"The task now facing Jacob Zuma is to reach out to the Mbeki supporters," he said.
"The task facing the former ANC president Thabo Mbeki is to create a means of working together with the man who succeeded him.
"One must remember as well that Mbeki has 18 months to run as South African president and obviously he is going to have to work very closely with the man who is now the leader of the ANC."Extended conflict
Adam Habib, political analyst, said: "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."
|Rival supporters heckled speakers |
from the opposing camps [AFP]
Zuma faces revived corruption charges in an arms scandal which saw him sacked as deputy president of South Africa in 2005.
The case now raises the possibility of him being jailed before he succeeds to the presidency.
The new ANC leader is a controversial figure who stood trial accused of raping a family friend half his age in 2006.
Although he was acquitted, he was widely ridiculed for testifying he had showered after sex with his HIV-positive accuser in order to prevent infection.
Senior ANC officials said Zuma's election was unlikely to lead to a shift in economic policy.
Kgalema Motlanthe, ANC deputy leader, said: "At the moment, there are no ideological differences ... The policy is in place and intact."
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.
Jeff Gable, ABSA Capital's head of research said: "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."
South Africa's 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.
Mbeki was handed the party leadership by Nelson Mandela in 1997 and succeeded him as head of state in 1999. After a decade of dominance he now has no official ANC position.