"Any suggestion of misconduct on his part, made now, years later, is entirely baseless," Terrence O'Donnell said in a statement that emphasized US authorities had investigated the joint venture at the core of the charges.
"The Department of Justice and the Securities and Exchange Commission investigated that joint venture extensively and found no suggestion of any impropriety by Dick Cheney in his role of CEO of Halliburton," he said.
His comments came after a spokesman for Nigeria's anti-graft agency, Femi Babafemi, confirmed plans to file charges as early as next week against the former vice president over a bribery scandal connected to the construction of a liquefied natural gas plant in southern Nigeria.
The spokesman would not give details on the charges except to say "they are not unconnected to his role as the chief executive of Halliburton."
A prosecutor on the case said joint charges would be filed at the country's high court in Abuja against Cheney, along with the former and current leadership of the energy giant and others.
Officials from companies in a consortium involved in the LNG plant would also be included in the charges to be "placed before the court at the latest by Tuesday of next week," said Godwin Obla.
Cheney would face conspiracy charges and a Nigerian judge would be asked to issue an arrest warrant for him that would be transmitted to Interpol, said Obla.
"As the CEO of Halliburton, he has the responsibility for acts that occurred during that period," Obla told AFP.
Companies in the TSKJ consortium involved in the plant included France's Technip, Snamprogetti (formerly a subsidiary of a company owned by Italy's Eni), Kellogg Brown and Root (KBR), and Japan's JGC.
KBR is a former subsidiary of Halliburton, where Cheney served as CEO before becoming vice president under George W. Bush following elections in 2000.
The LNG case involves an alleged 182-million-dollar cash-for-contract scandal over 10 years until 2005 over construction of the LNG plant in southern Nigeria. Halliburton has denied involvement in the allegations.
US authorities said last year that Halliburton and KBR had agreed to pay 177 million dollars to settle charges from the Securities and Exchange Commission in the United States.
KBR agreed to pay a further 402 million dollars to settle criminal charges brought by the US Justice Department.