Lamido Sanusi, Nigeria Central Bank Governor, has been suspended by President Goodluck Jonathan for financial recklessness and misconduct.
Sanusi he alleged that $20bn in oil revenue had gone missing.
Nigeria’s state oil firm has denied failing to account for the money, saying the claim was unsubstantiated.
Sanusi managed to reform Nigeria’s banking sector since his appointment in 2009.
Sanusi has indicated in the media that he plans to challenge his suspension in order to preserve Nigeria’s central bank’s independence.
Foreign exchange, bond and money markets have stopped trading because of uncertainty caused by the move, Reuters news agency reports.
Sanusi’s allegations threaten to expose high-level fraud in Nigeria’s notoriously opaque and corrupt oil sector.
Nigeria is one of the world’s biggest oil producers.
“The reality is anyone who challenges the oil sector is striking at the heart of the vested interests that control the Nigerian state and one should be ready for the consequences,” says Sanusi.