China's President Xi Jinping, Russian President Vladimir Putin, Indian Prime Minister Narendra Modi, and Brazilian President Michel Temer will attend the annual summit, along with several African leaders invited as guests.

Xi held talks with South African President Cyril Ramaphosa on the eve of the gathering, saying that "the Johannesburg summit has special significance for Brics cooperation in the new circumstances".

The Brics group, comprising more than 40% of the global population, represents some of the biggest emerging economies, but it has struggled to find a unified voice - as well as achieving sharply different growth rates.

Xi arrived in South Africa after visiting Senegal and Rwanda as part of a whistlestop tour to cement relations with African allies.

Signalling diplomatic rivalry over influence in Africa, India's Modi visited Rwanda and Uganda on his own five-day tour of the continent including the Brics summit.

The meeting opens on Wednesday afternoon with a business forum, before the heads of state hold talks on Thursday.

African leaders attending a "BRICS outreach" programme on Friday include Paul Kagame of Rwanda, Joao Lourenco of Angola, Macky Sall of Senegal and Yoweri Museveni of Uganda.

Turkish leader Recep Tayyip Erdogan will also attend a summit as the current chair of the Organisation of Islamic Cooperation (OIC) and will meet Putin on the summit's sidelines.

eNCA