The Pietermaritzburg High Court has declared that the ANC's provincial conference held in 2015 was "unlawful and void".
The judgment, handed down on Tuesday morning, comes after ANC members Lawrence Dube, Sibahle Zikalala, Martin Mzangwa, Mzweni Ngcobo and Lindiwe Buthelezi brought an application in 2016 alleging that there were a number of irregularities with the conference and that it was flawed.
Among their allegations, the members in court papers said the tweeting of results on the @myANC Twitter handle while voting was still under way proved the election was rigged; the provincial congress was held earlier than had been scheduled; and there had been voting irregularities.
Scenes outside the Pietermaritzburg High Court shortly after its decision. Video: Supplied
These included the voters roll being manipulated to favour certain branches and disadvantage others, and a number of bogus delegates being allowed to vote.
The court's decision affects the decisions made to elect members to the party's provincial executive committee including the election of the party's Sihle Zikalala as provincial chairperson defeating the then chairperson Senzo Mchunu.
It is not yet clear whether Zikalala and other members of the PEC, who were respondents in the case, would apply for leave to appeal the decision.