Corruption costs African countries an estimated 25% of its combined national income, Nigerian President Olusegun Obasanjo said - some $148bn a year.
Many African countries are conducting anti-corruption campaigns
The outgoing leader of the African Union called the problem "a preventable loss" and said that industries such as oil, gas and minerals were worst hit.
He blamed "unpatriotic citizens", who he said were looting African resources.
The West was collaborating, he added, by allowing the proceeds from graft to be held in banks outside Africa.
Speaking at the the Extractive Industries Transparency Initiative (EITI) in Abuja, Mr Obasanjo promised a "war against corruption" in Nigeria, which is notorious for graft.
Mr Obasanjo said revenue from extractive industries - mining and oil production - was "a major contributor to this monumental and preventable loss".
"The popular 'paradox of poverty in the midst of plenty' is a daily experience in many African countries rich in oil, gas and minerals," the president said.
"The majority of citizens in these countries still lack basic health and educational facilities."
EITI was formed as part of an effort to oblige governments to open their oil accounts to scrutiny, and to hold them accountable for their income.
"Unpatriotic citizens in our midst loot our resources and cart the proceeds away into Western banks with the collaboration of Western financial systems," Mr Obasanjo said, in comments quoted by the This Day newspaper.
"When we signed into EITI in 2003, we resolved to implement it through a model of coalition."
President Obasanjo blamed the prevalence of corruption revealed by recent audits on the "institutional decay and dislocation that our country suffered over the last two decades".
"Our challenge is to use the impetus granted us by these audits to transform our revenue reporting mechanisms, production institutions and human personnel for a more transparent extractive industry," he said.
He said civil society organisations could serve as "whistle-blowers that can complement our anti-corruption drive".