Businessman Christo Wiese owes the SA Revenue Service (Sars) R2-billion, the Sunday Times reported.
The amount apparently included a R1-billion tax bill and various penalties. Wiese was contesting the bill, levied on his main trading company, Titan, in tax court.
Wiese (71) chairman of Shoprite and Pepkor, however disputed the report.
"Do you think that for 50 years Sars has not been aware of my existence? I'm not hiding anywhere, so if you think I owe you money, send me the bill," the newspaper quoted him saying.
Sars spokesman Adrian Lackay would not comment on the matter.