(AFP) - BRICS leaders meet in South Africa on Tuesday as the loose association of major emerging economies seeks to assert its voice as a counterweight to Western dominance in global affairs.

The so-called BRICS nations -- Brazil, Russia, India, China and South Africa -- represent a quarter of the global economy, and interest in joining the club has surged ahead of its three-day summit in Johannesburg.

Security has been bolstered across the city where South Africa's President Cyril Ramaphosa will host China's President Xi Jinping, India's Prime Minister Narendra Modi, Brazil's President Luiz Inacio Lula da Silva and some 50 other leaders.

Russian President Vladimir Putin is the target of an international arrest warrant over alleged war crimes in Ukraine and will not attend in person, with Foreign Minister Sergei Lavrov sent on his behalf.

Representing 40 percent of the world's population across three continents, with economies at different levels of growth, the BRICS share a common desire for a global order they see as better reflecting their interests and rising clout.

The theme of its 15th summit is "BRICS and Africa" and comes as the continent emerges as a renewed diplomatic battleground with the United States, Russia and China jostling for economic and diplomatic influence.

On the eve of the summit, Ramaphosa said his country would "not be drawn into a contest between global powers" and strongly reaffirmed South Africa's long-standing policy of non-alignment.

"We will urge the international community to refocus on development issues, promote a greater role by the BRICS cooperation mechanism in global governance, and make the voice of BRICS stronger," China's Xi said in an editorial published in South African media on Monday.

- Division and demand -

There is growing interest in the bloc, which began as four nations in 2009 but expanded the following year with the addition of South Africa.

Ahead of this summit, at least 40 countries have expressed interest in joining including Iran, Saudi Arabia, Bangladesh and Argentina, officials say.

South Africa will present BRICS leaders with a proposal to expand its membership and a decision on the matter is expected at the summit's close.

But analysts are more cautious.

The issue of BRICS expansion is divisive, particularly among its two most powerful members, China and India.

China is keen to rapidly grow the bloc and widen its influence but observers say India is wary of the intentions of its regional rival.

"In my view, possible further extension will be considered during the course of this year and not decided at the summit to allow for more time," said Jannie Rossouw, a professor of global political economy at the University of the Witwatersrand in Johannesburg.

The BRICS operate on consensus and that presents "a major obstacle" to decision making, said Jakkie Cilliers, founder of the Pretoria-based Institute for Security Studies (ISS) think tank.

"In the long term, my view is that the inevitability of China-India rivalry is probably the major challenge that BRICS will eventually be confronted with," he told AFP.

© Agence France-Presse