Deepening rifts between ANC members in provincial regions could create a crisis for the ruling party, political analysts said on Monday.
Signs of internal tension were becoming more and more obvious, they said.
Rhodes University visiting professor of politics Steven Friedman cited the adjournment of the OR Tambo regional conference in the Eastern Cape last week, and the disbanding of the Ngaka Modiri Molema region in the North West.
"I think that this is something very serious. It is a potential crisis for the ANC."
Witwatersrand University analyst Susan Booysen said issues surrounding the leadership of branches and regions, were at "the heart of the battle of Mangaung" - where the party would hold its elective conference in December.
She said the party's last elective conference, held in Polokwane in 2007, changed the way the ANC thought about its leadership.
"Polokwane has made the branches wiser, and in a way it [the ANC] lost it's innocence.
"Since then we have more members lobbying for leaders. The majority of members who vote comprise of the branches, regions, and provinces."
"We know that there is a power struggle, and that there are different factions," he said.
The recent controversy around the OR Tambo region's elections showed tension in the party was "simmering".
Similar situations could affect the African National Congress's Mangaung conference.
Friedman said the ANC's national executive committee (NEC) had to rectify the situation in OR Tambo.
"The NEC needs to get involved, but not like how they are at the moment. It can't be like the intervention in Limpopo," he said.
"There needs to be free and fair elections [in the region], and they need to abide by the results. If that does not happen this could grow into a possible trend in the ANC."
He said disbanding the region's leadership, or putting provincial or national executive members in charge, was not the answer.
"It is like saying Parliament isn't working, so let's go ahead without Parliament. The situation can't be left alone, it needs to be fixed."
Booysen said with the audit of the ANC's membership, and the announcement of nominations, the party could face further upheaval.
"I'm afraid that there will be a huge disruption if things don't go in a particular way. The lead-up to Mangaung will see major battles."
She said members who opposed President Jacob Zuma' re-election as party leader no longer trusted the ANC's leadership.
"The opposition does not trust [the ANC's headquarters] Luthuli house anymore. We know that [ANC secretary general] Gwede Mantashe is in the Zuma camp, so how do we know if they [the leadership] are acting fairly or unfairly?
"There is no neutral territory or clear-cut intervention. This is a major battle in the ANC, and we ain't seen nothing yet."
The party's top six officials - Zuma, deputy president Kgalema Motlanthe, Mantashe, deputy secretary general Thandi Modise, chairwoman Baleka Mbete, and treasurer general Matthews Phosa - were reportedly having a meeting on Monday morning, where the OR Tambo conference was one of the topics up for discussion.
The Eastern Cape PEC took control of the region last week after its conference was adjourned without any newly-elected leaders. The event was dogged by allegations of inflated membership figures and "ghost" delegates.
Provincial secretary Mlibo Qoboshiyane said at the time that the electoral commission at the conference discovered that votes were cast by 591 delegates, instead of the 587 adopted by plenary.
The region is the largest in the Eastern Cape, and the second-largest ANC region in the country after eThekwini in KwaZulu-Natal - Zuma's home province.
Party members opposed to the North West's leadership protested at the ANC's headquarters in Mahikeng in May.
The action followed a decision to disband the party's Ngaka Modiri Molema regional leadership, which allegedly shared the ANC Youth League's view that Zuma needed to be replaced in Mangaung. The disbandment was reportedly seen as an attempt to give Zuma's chances for re-election as ANC president a boost.