The Gupta family laid bare their business dealings in a two-page advertisement in their newspaper The New Age under the headline "Gupta family: The Inconvenient Truth".
"We have been quiet until now but given the recent xenophobic and hate speech directed towards us, now is the time to set the record straight," news24 online quoted the family as having said in the advertisement.
"Our interaction with the current president began in 2000, which was long before he became president," they said.
"It is absurd to suggest that we benefit from government business when only less than one per cent of the (family's) business is with the South African government."
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The family's reaction came two days after Deputy Finance Minister Mcebisi Jonas in a public statement said the Guptas had last year offered him the top cabinet position, shortly before Zuma sacked the respected Nhlanhla Nene in December.
The ruling African National Congress, which led the struggle to end apartheid, today began a three-day meet of its national executive where the scandal is likely to dominate.
The ANC has warned that the country risks becoming a "mafia state" if corruption is not tackled.
The Gupta brothers Ajay, Atul and Rajesh, who built up an array of companies with interests in computers, mining, media and engineering, after moving to South Africa in the early 1990s, have denied the allegations, saying they are the victims of a plot.
In the advert today, the family expalined in point-form how Atul Gupta arrived in South Africa in 1993, and that by 2000 the whole family had settled there, the report said.
They claimed that the "ground reality" has been that in the 10 years that they have applied for 100 different mining licences, none were successful, it said.