BRICS, a loosely-defined group which sees itself as a counterweight to Western economic domination, derives its name from Brazil, Russia, India, China and South Africa. The bloc has previously indicated it is open to expansion.
"Twenty-two countries have formally approached BRICS countries to become (a) full member of BRICS, there's an equal number of countries that have been informally asking about becoming BRICS members," South Africa's ambassador-at-large for Asia and the BRICS, Anil Sooklal, told media in Johannesburg.
He listed Iran, Argentina, Bangladesh and Saudi Arabia among nations that have expressed an interest.
Growing interest in the bloc is not new but reflects the "confidence" in the work that BRICS has been "championing" over nearly a decade and a half, he said.
BRICS is not only "a power force ... in trying to change the faultlines in terms of global politics, but it is also changing what is happening in the economic space globally," he said.
"The current global architecture continues to be unequal, continues to marginalise developing countries... and continues to be dominated by a few hegemons. We don't want such a world. We want a world where our voices are heard," he told AFP.
South Africa will host the BRICS summit in Johannesburg between August 22-24 to which a total of 69 countries have been invited, including all African states.
French leader Emmanuel Macron has asked to attend the summit but no decision has been reached yet on that request.
"BRICS is a consensus entity, it's not South Africa's decision alone, this has to be consulted," said Sooklal, adding that Foreign Minister Naledi Pandor "is busy with that process".
"There is high interest in the summit," said Sooklal.
Formally launched in 2009, BRICS now accounts for 23 percent of global GDP and 42 percent of the world's population, according to the summit's website.