Duduzane Zuma, the son of South Africa’s President, said on Thursday there was “nothing untoward” about his links with the Gupta brothers – businessmen accused of using their friendship with his family to win contracts.

Duduzane told the BBC in a rare interview he had built up his own ties with the Gupta brothers purely through being “a likeable guy”.

“I’ve not involved myself in any corrupt practice, in any corrupt business,” he said.

The Guptas – a family of Indian-born businessman – have dismissed accusations by members of the ruling African National Congress party of using their link to the president to boost their businesses that span mining and technology and have government contracts.

President Jacob Zuma has faced calls to resign from the opposition and also within the usually united ANC over the relationship and the allegations of influence wielding that have shaken the government and markets. He has also denied any wrongdoing.

The main opposition Democratic Alliance (DA) party has said Duduzane helped produce a racially-charged PR campaign backing his father while he was working for Oakbay Resources, which was controlled by the Guptas.

The DA based its allegations on tens of thousands of leaked emails released by investigative journalists – though one of the Gupta brothers, Atul Gupta, said this month the emails were fake.

Duduzane said in April last year he would sell his investments in a mining firm owned by Oakbay Investments – a holding company for Gupta businesses in South Africa.