Afrikaans Sunday paper, Rapport, reports this morning that businessman, Christo Wiese, owes the Sars about R2 billion.
It is reported that a long-term investigation has brought to light how Wiese channeled funds to a network of trusts, private companies, and off-shore accounts.
The paper quotes "immaculate" sources and says the investigation is ongoing.
Wiese is the third-richest man in South Africa, with his wealth only surpassed by that of Nicky Oppenheimer and Johann Rupert.
According to Forbes, he is worth about R25 billion. He is the 367th richest man in the world.
SARS' investigation was reportedly triggered by an incident, in 2009, where Wiese was detained by British customs officials and had about R8 million confiscated that he was carrying with him in cash.
The money was recently retuned following a legal process and, according to his lawyer, represents less than two weeks' income for Wiese.