Reports from New York, where Buhari has been attending the UN General Assembly, quoted the president as saying he would be minister of petroleum resources, with a junior minister taking charge of day-to-day affairs in the sector.
“Confirmed. He said so,” his spokesman Femi Adesina told AFP in a text message, without giving further details.
Buhari, 72, took office on May 29 after a landmark election victory against Goodluck Jonathan — the first time an opposition candidate has unseated an incumbent in the country’s history.
The former military ruler has vowed that corruption and the corrupt will have no place in his government and vetting of potential candidates has been seen as delaying his appointment of a senior ministerial team.
Buhari has made tackling the rot in the oil sector a priority, as he seeks to cut endemic graft and put the country’s crippled, crude-dependent finances on a firmer footing.
Nigeria — Africa’s number one crude producer and biggest economy — has been hit badly by a slump in global crude prices since last year, squeezing government revenue.
Oil accounts for some 90 percent of Nigeria’s foreign exchange earnings.
The president has vowed to recover “mind-boggling” sums of stolen oil cash, starting with a drastic overhaul of state-run oil firm the Nigerian National Petroleum Company (NNPC).
The NNPC has become a byword for corruption and last year was accused of failing to remit $20 billion in revenue to the central bank.
Buhari helped establish the NNPC in 1977 as oil minister under military ruler General Olusegun Obasanjo.
He was later in charge of the Petroleum Trust Fund during the time of General Sani Abacha in the 1990s.
Buhari’s caution in appointing ministers has seen him nicknamed “Baba Go Slow” in Nigeria, but he has promised to name his cabinet by Wednesday.
Appointments have to be approved by parliament, which resumed sitting on Tuesday.
A committee advising Buhari on policy before he took office has recommended he streamlines the number of ministries and ministers.
Meanwhile, according to the Senior Special Assistant (SSA) on Media and Publicity to the President, Garba Shehu, President Buhari on Wednesday, departed the United States for Abuja after a successful outing at the 70th session of the UN General Assembly in New York.