"In all its manifestations, factionalism has become the biggest threat to the organisation. It is because of factionalism that we have seen the emergence of splinter groups over the past ten years which negatively affected our movement both quantitatively and qualitatively," Zuma said addressing thousands of delegates on the first day of the 54th national elective conference at Nasrec in Johannesburg.
"Slate politics, another manifestation of factionalism, has also cost us many good and capable comrades in whom our movement has invested significantly."
The outgoing president also lamented what he termed a growing trend of ill discipline amongst members of the party.
"Ill-discipline has also continued to afflict the ANC which has taken new forms in the recent past, bordering on members publicly challenging the authority of the organisation," said Zuma.
"There have also been worse incidents of ill-discipline where members openly side with, and work with opposition parties and other formations that are hostile to the ANC, against positions adopted by the movement."
He said the liberation movement needed to reaffirm its authority over individual members.
"There should be consequences for any member who acts and speaks contrary to the values, principles and political programme of the ANC," said Zuma.
African News Agency/ANA