The Senate on Wednesday mandated three of its committees to investigate seven international oil companies over their alleged refusal to remit about $21bn to the national treasury.

The decision of the upper chamber was sequel to a motion by the Vice Chairman, Senate Committee on Petroleum Resources, Ifeanyi Ubah.

Ubah had drawn the attention of his colleagues to the IOCs alleged refusal to honour the provisions of the Production Sharing Contracts Act.

The Act of the National Assembly, according to the senator, regulates the sharing of additional revenue between the Nigerian National Petroleum Corporation and the various oil companies.

The Deep Offshore and Inland Basin Production Sharing Contract Act Cap D3 LFN 2004 became effective on January 1, 1993 and was first reviewed in 2004.

He said that the legislation was due for review in 2008 after 15 years.

He added that the provisions of PSC Act also stipulated that it should be subjected to a five-year periodic review, which should have started in 2013.

He said as a result of the non-review the PSC Act, the Federal Government had lost about $21bn over a period of 20 years as confirmed by the Minister of State for Petroleum Resources after a  meeting of the Federal Executive Council on the 14th December, 2017.

He said the PSC Act anticipated the necessity for post execution and periodic review to ensure that government derived maximum and equitable benefits.

Uba noted that a review was to be undertaken whenever the price of crude oil exceeded $20 per barrel in order to increase revenue accruable to the government.