South African Finance Minister Malusi Gigaba said on Friday he was worried about the influence of a wealthy family accused of using its friendship with President Jacob Zuma to secure contracts with state-owned companies.

Gigaba’s unusually strong comments came the day after power utility Eskom suspended its chief financial officer Anoj Singh pending an investigation into allegations that he granted preferential treatment to firms linked to the Gupta family, business friends of Zuma.

Gigaba is close to Zuma and seen as an ally. He took office after Zuma fired highly respected finance minister Pravin Gordhan in a March cabinet reshuffle.

Singh, the Gupta family and Zuma have denied any wrongdoing.

“Like all South Africans, I am very worried about them and I think we need to establish fact from allegation,” Gigaba told the Cape Talk radio station when asked about a slew of leaked emails that have detailed the Gupta family’s business dealings.

“The allegations are quite damaging to the investor perceptions, as well as ratings agencies, of the governance of our state-owned companies,” Gigaba said.

He also said he supported the establishment of a commission of judicial enquiry, called for last year by South Africa’s top anti-graft watchdog, to investigate the mounting allegations swirling around the family.

A number of international companies have been drawn into the widening scandals, including Germany’s SAP and Software AG, and global consultancy McKinsey.