An independent panel of experts, headed by former Irish president Mary Robinson, has cleared the beleaguered leader of the African Development Bank (AfDB) of corruption, according to a report obtained by AFP.

Akinwumi Adesina, 60, a charismatic speaker known for his elegant suits and bow ties, became the first Nigerian to helm the AfDB in 2015 -- but a 15-page report earlier this year claimed that under his watch the bank had been tarred by poor governance, impunity, personal enrichment and favouritism.

The panel of three experts, led by Robinson alongside Gambia's Chief Justice Hassan Jallow and the World Bank's former integrity vice president Leonard McCarthy, cleared Adesina of all charges alleged by whistleblowers.

"The Panel concurs with the Committee in its findings in respect of all the allegations against the President and finds that they were properly considered and dismissed by the Committee," Monday's report concluded.

The African banking institution and Adesina -- who is the sole candidate for the bank's August's presidential elections -- has been battered by the rollercoaster of allegations after the whistleblowers' complaints were leaked to the media in April.

The former Nigerian finance minister had always declared himself "innocent" of the charges.

Robinson -- who led Ireland from 1990 to 1997 before serving as the United Nations High Commissioner for Human Rights until 2002 -- dismissed the 16 whistleblower allegations against Adesina.

Adesina, 60, a charismatic speaker known for his elegant suits and bow ties, became the first Nigerian to helm the AfDB in 2015
Adesina, 60, a charismatic speaker known for his elegant suits and bow ties, became the first Nigerian to helm the AfDB in 2015 AFP / Kola SULAIMON

The panel did not investigate the charges themselves, as that was not within their mandate.

The AfDB plays an important if largely behind-the-scenes role in African economies, financing projects in agriculture, health, energy, education, transport and other development sectors.

Nigeria, Africa's most populous nation and largest economy, has firmly backed Adesina in the face of the allegations.

Nigerian President Muhammadu Buhari said the panel's report "validates his competence and integrity to lead" the bank.

"This conclusion of the review of the Report of the Ethics Committee should finally draws a curtain on the allegations that have created distractions for the institution in recent months," Buhari said in a statement on Twitter.

"I urge Dr. Adesina to remain steadfast, dedicated and resolute in pursuing his noble goals for the Bank, especially with the now-expected second term in office."

Nigeria African development bank