DA leader Mmusi Maimane has called for an independent inquiry to look into the donation made by Bosasa to fund Ramaphosa's ANC presidential campaign.
Two weeks ago in the National Assembly, Ramaphosa claimed the donation was given to his son, Andile, because he had a business relationship with Bosasa.
But Andile immediately distanced himself from any dealings with the company.
On Friday, Ramaphosa, through a letter, made an about-turn and revealed that the R500000 paid by the company was, in fact, a donation towards his ANC presidential campaign last year, without his knowledge.
"I will be writing to president Cyril Ramaphosa today [yesterday] to request that he appoints an independent inquiry headed by a retired judge to be selected by the chief justice to fully investigate the Bosasa scandal, which now involves the president and his family," said Maimane.
The DA leader said Ramaphosa must appoint an independent inquiry to investigate Bosasa's "enormous and likely corrupt influence" on the government and the ANC.
EFF leader Julius Malema said Ramaphosa should come clean over the Bosasa matter.
"The president must tell us where did the money to support his campaign come from because it looks like it's not only R500000.
"Can he open the books [financial statements]? ...But since when do you need money to campaign for presidential position of a political party?" asked Malema.