President Muhammadu Buhari's doctors have advised him to take things slowly as he recovers from an undisclosed illness, and there is no need to worry about his health, his spokesman said on Thursday.

Buhari did not attend a cabinet meeting on Wednesday, choosing to rest and work from home. That triggered speculation about his health and his ability to run Africa's biggest economy and most populous nation.

Wednesday's was Buhari's third consecutive absence from the weekly meeting chaired by Vice President Yemi Osinbajo.

Garba Shehu said Buhari's decision not to attend the meeting was last minute, otherwise he would have notified his cabinet and Nigerians.

Buhari, 74, returned home in March after nearly two months' medical leave in Britain and said he would need more rest and health tests. Details of his medical condition were not disclosed.

"President Buhari himself, on his return to the country, made Nigerians aware of the state of his health while he was in London. Full recovery is sometimes a slow process, requiring periods of rest and relaxation," Shehu said in a statement.

"Despite his lack of visibility, Nigerians should rest assured that President Buhari has not abdicated his role as Commander-in-Chief of Nigeria."

Shehu said the president received daily briefings on activities of government and met regularly with his vice president.

Osinbajo, a lawyer who is seen as more business-friendly than Buhari, has played an active role in driving policy changes, chairing cabinet meetings during the president's medical leave.

Shehu said Buhari was spending most of his time in his private residence which is equipped as an office, adding that he had gone through the worst period of his recovery in London.

Reuters