Mr Zoellick, who was nominated by US President George W Bush, will replace Paul Wolfowitz, who leaves on 30 June.

Mr Wolfowitz is stepping down after two years in office, following a scandal over his role in winning a pay and promotion package for his partner.

A former US deputy secretary of state, Mr Zoellick has most recently worked for investment bank Goldman Sachs.

'Encouraging hope'

Under an unwritten agreement, the US chooses the head of the World Bank, while European countries select the leader of its sister institution, the International Monetary Fund.

Mr Zoellick's nomination was considered by the World Bank's 24-member board of governors on Monday, and he will start work on Sunday, 1 July.

Mr Zoellick brings to the bank presidency strong leadership and managerial qualities

World Bank statement

Challenges facing new boss Choosing a World Bank boss

Mr Zoellick said he was "eager to meet the people who drive the agenda of overcoming poverty in all regions, with particular attention to Africa".

He also said he looked forward to advancing social and economic development, investing in growth, and "encouraging hope, opportunity, and dignity".

"I know of the staff's passion for this mission. And I respect the staff's proud record, continuing search for learning and improvement, and commitment to results," he added.

As deputy secretary of state, Mr Zoellick was chief aide to Condoleezza Rice between February 2005 and June last year.

He is also an ex-US trade representative.

'Proven track record'

The president of the World Bank serves a renewable, five-year term.

"Mr Zoellick brings to the bank presidency strong leadership and managerial qualities as well as a proven track record in international affairs and the drive required to enhance the credibility and effectiveness of the bank," the World Bank board said in a statement.

The executive directors also "affirmed the important role of the bank in addressing poverty and economic growth".

Meanwhile, the UK International Development Secretary, Hilary Benn, said: "I would like to offer my congratulations to Bob Zoellick on his appointment.

"I look forward to working with him and the bank in the fight against poverty across the world."