Robert Zoellick on Thursday revamped the top management structure of the World Bank, bringing in Ngozi Okonjo-Iweala, a former Nigerian finance and foreign minister, as one of his top deputies and shaking up the portfolios of his other two managing directors.

Ms Okonjo-Iweala, who worked at the bank for 21 years as a development economist, will become managing director for Africa, South Asia and Europe and central Asia. These regions include most of the borrowers from IDA, the bank’s concessional loan facility. She will also be in charge of human resources - a sensitive area following disputes over appointments made by former president Paul Wolfowitz - with a brief to encourage diversity.