ANC Secretary-General, Fikile Mbalula, has confirmed the party has given former Eskom CEO, Andre De Ruyter, an ultimatum.
It wants him to give evidence on allegations he made of political meddling and corruption at Eskom.
He has to do this within seven days, or face a lawsuit.
The former CEO claims the utility has been looted for decades.
He also alleges cabinet ministers and other well-connected officials have had a hand in the looting.