ABUJA: Nigeria's senate president said that despite forces "working desperately" to derail a long-delayed oil overhaul bill, lawmakers will push the bill through the national assembly.

The measure, 20 years in the making, underpins everything from oil exploration to gas pipelines and fuel regulation. President Muhammadu Buhari sent it to the senate in September, and it passed a first reading in both chambers before the end of 2020.

The bill would change the structure of state oil company NNPC, amend oil and gas taxes and revenue-sharing and create new regulatory bodies, among other things, to make Nigeria's oil sector more dynamic and efficient.

The laws governing Nigeria's oil and gas exploration have not been fully updated since the 1960s because of the contentious nature of any change to oil taxes, terms of exploration, and revenue-sharing.

With the other key bill - the 2021 budget - now signed into law, the petroleum bill will be the first priority when the national assembly reconvenes later this month.

Senate President Ahmad Lawan said that people inside and outside Nigeria were fighting to scuttle the oil reform.

But he likened the bill to a law passed in 2019 to increase the government's take of offshore oil revenues, one that oil companies opposed and regarded as a "joke", he said.

The national assembly passed it within weeks of introduction and it was quickly signed by Buhari.

"That is what we intend to do with the PIB (Petroleum Industries Bill) by the grace of God," Lawan said.