Nigerian National Petroleum Corporation (NNPC) has weighed overall losses in nation’s oil revenues in 2013 amounting to $518m due to inefficiencies in oil swaps and offshore processing agreements, reported Vanguard.

Executive Secretary of Nigeria Extractive Industries Transparency Initiative (NEITI), Waziri Adio, said that Nigeria thus lost $211.88m to crude for product swap and $306.16m of offshore processing agreements.

Further, Adio revealed that the NNPC and its subsidiaries have blocked an amount of $3.8b that was due to be paid to the Nigerian government.

As a result, the Economic and Financial Crimes Commission, EFCC, will soon commence investigations into the matter.

Nigeria’s oil market has recently been unstable due to the series of a series of attacks from militants of the Niger Delta Avenger group, pushing production in spring to 30-year lows, which eventually brought the country’s crude oil output at risk.