A programme of the three-day summit, issued on Friday by the provincial structure, indicated that Zuma would address delegates on Sunday.
In Zuma’s place, African National Congress deputy secretary-general Jessie Duarte gave a brief speech.
Former arts and culture minister Paul Mashatile was re-elected chairman of the province, while premier David Makhura was elected deputy chairman.
Earlier, party spokesman Zizi Kodwa said Zuma could not speak at the conference because he had another function to attend.
“Other people had pre-arranged programmes which unfortunately could not be changed… He [Zuma] was hoping [to] finish on time today, but the programme is keeping him long.”
He explained that Zuma had to attend an education trust function in KwaZulu-Natal on Sunday, despite being scheduled to deliver closing remarks at the ANC conference at 1pm.