By Gordon Bell

JOHANNESBURG, May 26 (Reuters) - South Africa urged the United States on Saturday to abide by an agreement of the Group of 20 economic powers for an open and transparent appointment of the new head of the World Bank.

The G20, in the final communique of its 2006 annual meeting, called for the managing director of the International Monetary Fund and president of the World Bank to be selected in a transparent and consultative process, and not restricted to nationality.

"These communiques are so carefully negotiated and every single word gets approved line-by-line and reflects the views of those who participated," Thoraya Pandy, spokeswoman for South Africa's Finance Minister Trevor Manuel, told Reuters.

"It would be fair to say that those who participated in the agreement should be bound by it." South Africa is the current chair of the G20, which also includes the United States.

The U.S. government looks set to appoint an American as the new head of the bank following the resignation of Paul Wolfowitz over accusations he authorised a pay rise for his companion.

This is in line with a past understanding that Washington appoints the president of the bank and a European leads the IMF.

The statement follows comments by Manuel -- once touted as a possible candidate to succeed Wolfowitz -- in a speech to parliament on Thursday in which he appealed for fairer treatment of poorer nations within the two institutions.

This would be a key focus of the G20 during South Africa's year as chair.

"Interesting issues have just arisen again (such as) past decisions about the need for transparency on the appointment of individuals to key institutions like the president of the World Bank and managing director of the IMF," Manuel said on Thursday.

Pandy said South Africa's stance was in line with those of Brazil and Australia, which together formed the troika of past, sitting and future chairs of the G20.