Former British minister Peter Hain on Monday accused international corporations and banks of abetting graft in South Africa.
Testifying at a commission probing state corruption under former President Jacob Zuma, Hain -- a former anti-apartheid activist who served in past Labour governments -- charged international banks, corporations and governments with facilitating the looting of state funds.
"It should be a source of shame for the international community and these banks and professional enablers that they have facilitated this," said Hain, now a member of the House of Lords.
"Some of these corporations are based in New York, London, Hong Kong and Shanghai," he added, referring to HSBC, Standard Chartered and the Bank of Baroda by name.
The Indian-born Gupta brothers -- Ajay, Atul and Rajesh -- are at the centre of a South African investigation into rampant corruption under Zuma's nine-year administration.
The US Treasury blacklisted the Guptas and froze their assets last month, calling them a "significant corruption network" that dispersed bribes and misappropriated millions in state funds.
The South African-born Hain, who also penned a book on Nelson Mandela, said the banks were still allowing the Guptas to open bank accounts, possibly for illicit money transfers.
He blasted banks for not applying the same "stringent measures" they put on ordinary citizens and criminals, and called on them to help return funds to the country.
"(The) Indian authorities should be trying to repatriate Gupta assets to South Africa," Hain said.
Numerous government officials and businessmen have voluntarily appeared before the commission, which was launched in August 2018 and is chaired by Deputy Chief Justice Raymond Zondo.
Their testimonies have gripped TV audiences across the country.
Zuma was forced to set up the enquiry in January 2018, shortly before he left office, after failing in a legal battle to overturn the ombudsman's instructions.