South Africa's radical leftist opposition party on Saturday urged the leaders of China, India and Brazil to boycott the BRICS summit next month in solidarity with Russia's Vladimir Putin, who will not be attending.

At an anniversary rally for the South Africa's third-largest party, the Economic Freedom Fighters (EFF), leader Julius Malema called on the remaining BRICS leaders to also skip the August 22-24 summit in a show of support for Putin.

"We call on the president of the People's Republic of China, India and Brazil not to come to (the) BRICS summit in solidarity with President Putin," Malema said.

Malema also denounced the United States for "threatening" South Africa by demanding it turn against the Russian leader in exchange for remaining part of the landmark African Growth and Opportunity Act (AGOA), which grants duty-free access for most exports.

"They can take away AGOA and leave us with our sovereignty," the 42-year-old said, addressing a a packed stadium of over 90,000 supporters donning the party colour red.

Malema condemned the corruption of the ruling African National Congress (ANC), which has governed the country since the advent of democracy in 1994, promising to oust them in the next election.

In March, the EFF organised a national protest in a bid to force President Cyril Ramaphosa to step down over his handling of the country's sickly economy and crippling energy crisis.