The Central Bank last year reported nearly USD 50 billion worth of oil sold by the state oil corporation had not been paid to the government.
In December the Finance Ministry reported it had accounted for all but USD 10.8 billion.
The Senate Committee on Finance heard yesterday that the unaccounted amount has grown to USD 20 billion. Finance Minister Ngozi Okonjo-Iweala told senators the Nigerian National Petroleum Corp has produced receipts to account for the USD 10.8 billion.
Committee chairman Sen Ahmed Makarfi concluded they did not have the expertise to unravel the mystery and said senators are ordering an audit by legal experts. Corruption and mismanagement are rife in Africa's biggest oil producer.