The Democratic Alliance has asked the South African Revenue Service to investigate President Jacob Zuma's financial affairs.
According to iol.co.za, the opposition party has asked Sars to investigate whether Zuma and various reported benefactors had paid the necessary taxes.
Sars spokesperson Adrian Lackay has confirmed to the Cape Argus that Sars is obliged by law to follow up any such complaint.
Last Friday the Mail & Guardian reported on an auditors' document, which was kept hidden when the National Prosecuting Authority (NPA) abandoned its prosecution of Zuma.
The report exposes the president as a "kept politician" who accepted money and favours on a routine and increasingly extravagant basis not only from former financial advisor Schabir Shaik, but also from other benefactors, including Nelson Mandela.
The DA's spokesperson for finance, Tim Harris, said he wrote to Sars commissioner Oupa Magashula "to request that he investigate whether or not President Jacob Zuma and his donors paid the appropriate taxes arising from the funds – allegedly amounting to more than R7-million – transferred to him between 1995 and 2006".
The report said that in terms of the Income Tax Act, many of the alleged payments to Zuma could have been classified as donations.
"If this is indeed the case, then they may well have been subject to donations tax … This, of course, assumes that President Zuma accepted the donations without rendering any services in exchange. If this was not the case, then the transfers could instead form part of the president's 'gross income' and be subject to normal income tax."
The DA's federal chairperson James Selfe said in a statement on Friday that the revelations justified the need to review the decision to drop corruption charges against the president, and called for the president to step aside while investigations took place.
The party took legal steps to secure documents, including the so-called "spy tapes", that could shed light on how the NPA came to that decision. Despite court backing it has so far been unsuccessful.
"The DA has been waiting since March this year for the record of decision which led to the corruption charges being dropped. Both the National Prosecuting Authority and Zuma's legal team have used every delaying tactic in the book to ensure that we do not obtain this record," he said.
Selfe said there was now sufficient grounds to establish that the decision to drop charges against Zuma was "both irrational and unlawful" and that the DA believed it would be "quite possibly justified" in going directly to court to review the decision without having to wait for the record.
"Subject to the advice of our advocates, this is exactly what we propose to do," he said. "The full story will come out eventually, but until then Zuma must take a leave of absence from his office until these allegations have been proved or discounted," he said.
The ANC last Saturday said it would not be commenting on the matter.
"We can't comment on a private matter as an organisation. It has nothing to do with anybody," spokesperson Keith Khoza said.
The ANC would not discuss the report with Zuma either, on the grounds that his finances were private.
"We cannot dignify irresponsible reporting by the Mail & Guardian; this has got nothing to do with the public office and the office of the president."