Outgoing World Bank president Robert Zoellick said Friday that emerging markets were well represented among the Bank's staff as he sought to deflect criticism of the US lock on the top job.

A nearly seven-decade carve-up has seen Americans lead the World Bank and Europeans head its sister organisation the International Monetary Fund.

But this year that is facing an unprecedented challenge from two developing-nation candidates, reflecting the increasing importance on the world stage of emerging economies.

"The top leader is an important role but not by any means the sole role," Zoellick, a former US diplomat, told a news conference in New Delhi.

"It is important to look throughout the organisation," said Zoellick, who was in the Indian capital after visiting a World Bank project in the poverty-stricken eastern state of Orissa.

During his five-year stint as World Bank president, Zoellick said he had recruited many senior staff from developing nations and also stressed that the United States did not dominate all multilateral institutions.

"An American has never headed the IMF, there has never been an American UN Secretary General," said Zoellick, who steps down in June. "Neither has an American headed the World Trade Organisation."

He said it was important for US officials to hold leadership positions in some international institutions in order to keep the United States supporting them.

"I would suggest if you want to keep the US engaged in multilateral organisations, you have to keep openings somewhere -- but that may or may not be at the Bank," he said.

"That's because the issue I have to fight against is people wanting the US to move away from such organisations."

Zoellick's comments came after a summit of the world's emerging powers on Thursday in New Delhi emphasised the need for an "open and merit-based" selection process in choosing the leaders of the World Bank and the IMF.

The leaders of the BRICS bloc -- Brazil, Russia, India, China and South Africa -- said they "welcome the candidatures from the developing world" for the new head of the World Bank.

The US choice, Jim Yong Kim, a Korean-American physician, is facing a challenge for the job from Nigerian finance minister Ngozi Okonjo-Iweala and Jose Antonio Ocampo, a former Colombian finance minister.

Even with calls for a change in the selection process, the US nominee is all but certain to be chosen as president by the Bank's 25-member board, experts say. The Bank says it expects to announce Zoellick's successor by late April.

Zoellick said he welcomed a plan by the BRICS nations to examine setting up a new development bank as a potential counterweight to other multilateral lenders such as the World Bank and the Asian Development Bank.

But he cautioned that setting up such an institution "is not an easy task -- you have to agree on the structure, the location, who is going to put up the capital.

"I don't mean to sound cool to the idea but there will be challenges."