Nigeria's President Bola Tinubu has asked the Senate for an extra 6.2 trillion naira ($4 billion) in funding to plug shortfalls in this year's national budget, according to a letter read to lawmakers on Wednesday.

Tinubu also sought to impose a one-off windfall tax on banks' foreign exchange gains, as his government aims to raise revenues to fund "capital infrastructure development, education, and healthcare as well as welfare initiatives."

Senators immediately started debating a bill to approve the new funding request, which comes at a time when the government is under pressure from unions to agree a new minimum wage amid the country's worst cost of living crisis in a generation.

($1 = 1,555.0000 naira)

(Reporting by Camillus Eboh; Writing by MacDonald Dzirutwe; Editing by Hugh Lawson, Alexandra Hudson)