JOHANNESBURG, April 8 (Reuters) - South African President Jacob Zuma's son, Duduzane, will sell his investments in a mining firm owned by friends of his father amid speculation that the wealthy Indian-born family is wielding undue influence on domestic politics.
Duduzane's announcement on Friday comes days after First National Bank, a unit of FirstRand, joined three other South African companies in quitting as bankers and auditors of companies owned by the Gupta family.
Citing "aspersions" against his family, Duduzane said he would also step down as a director of Shiva Uranium, the main subsidiary of Oakbay Resources, the Guptas' main mining holding company.
"I have decided to relinquish all positions that I hold at Oakbay companies and am exiting investments to preserve the jobs of Oakbay's thousands of employees and to de-politicise my participation in business," he said.
The mine is 26 percent-owned by Islandsite 255, a company of which Duduzane is also a director. It employs 648 people, the family said last month.
Allegations of the Guptas meddling in politics surfaced last month when deputy finance minister Mcebisi Jonas said they offered him the position of finance minister shortly before Zuma sacked his boss, Nhlanhla Nene, in December, a move that sent markets into a tail-spin.
[READ: FNB declines to give reasons for closure of Guptas' accounts]
Zuma has denied numerous allegations of the Guptas wielding undue political power. The Guptas have also dismissed reports of their alleged influence, saying they are pawns in a political plot to get Zuma out of office.
Oakbay, which said it had created 3,500 jobs in South Africa's mining sector, also said in a statement that chairman Atul Gupta and chief executive Varun Gupta had resigned with immediate effect.
"This decision follows a sustained political attack on the company," it said in a statement.
Unlike Duduzane, their statement made no reference to reducing their shareholding in the company.
Citing association risk, the local unit of global auditing firm KPMG cut ties with Oakbay last month. Other companies that have severed links are investment bank Sasfin and lender Barclays Africa. (Reporting by Tiisetso Motsoeneng and Ed Cropely; Editing Joe Brock)