Nigeria is to break up its state-run oil and gas firm into 30 separate companies, the country's junior oil minister announced, as part of wider plans to overhaul the corruption-ridden operation.

Emmanuel Ibe Kachikwu told an energy conference in Abuja on Thursday the move was designed to make the Nigerian National Petroleum Corporation (NNPC) more efficient.

"For the first time we are unbundling the subset of the NNPC to 30 independent companies with their own managing directors," said Kachikwu, who is also group managing director of the NNPC.

"Titles like 'group executive directors' are going to disappear and in their place you are going to have chief executive officers and they are going to take responsibilities for their titles."

Reform of the NNPC began last year when President Muhammadu Buhari sacked the entire board and appointed Kachikwu, an experienced oil executive formerly with ExxonMobil.

He has promised to uproot the firm's "anything goes" culture, overhaul opaque practices and warned of sackings for under-performance.

Losses at the NNPC have been reduced from 160 billion naira ($797 million, 723 million euros) to 3.0 billion naira by January this year, Kachikwu told delegates, promising a profit by the end of the year.

Buhari, who was elected last year on an anti-corruption ticket, has vowed to recover what he said were "mind-boggling" sums of money looted from government coffers in previous administrations.

Nigeria is Africa's biggest oil producer and relies on the sector for the majority of its revenue but the country has been hit hard by the fall in global crude prices since mid-2014.

Kachikwu said some oil-producing countries would meet in Moscow on March 20 to discuss a way out of the slump.