The World Bank must concentrate its activities to avoid over-reaching itself and duplicating other agencies' work, according to the international committee of government ministers which sets the bank's policy.

The development committee, which brings together finance and development ministers from member countries, said the bank should work out "an appropriate division of labour" between itself and agencies such as the United Nations Development Programme.

Clare Short, development minister, told the committee: "Until we know more, it is premature to take firm decisions about the World Bank's role. The World Bank should take a selective approach and be guided by its development and poverty reduction mandate."

Over the past year, the bank has developed a focus on providing "global public goods" such as developing vaccination programmes against communicable diseases. The development committee's communique was a clear indication that this movement must not be allowed to displace its other work. "We must ensure that a proper focus by the World Bank on these issues does not eclipse other critical development priorities," Ms Short said.

The committee was divided over a US proposal that lending to middle income countries should be more selective, and that higher charges on lending should be made to countries that had greater access to private sources of lending. "We have not reached a consensus in this regard," said Yashwant Sinha, the Indian finance minister who chairs the committee.

The World Bank's commitment to extending its role was clear from a report it released yesterday arguing that reducing corruption in government could double national income in developing countries.

In a further move away from a narrow focus on pure economic growth as the primary weapon against poverty, the report said that the "quality of growth" - including such elements as good governance and protection of the environment - was equally important.

"The pace of growth has been more sustainable in developing and industrialised countries that pay attention to the qualitative attributes of the growth process," the report said.

Improving the rule of law in particularly corrupt countries such as Ukraine and Indonesia to the levels of countries such as the Czech Republic or South Korea could double income per head over the medium term.

The report reflects a widening of the bank's role to include softer issues such as governance and education, which have increasingly supplanted its traditional role of financing large infrastructure projects in developing countries.

James Wolfensohn, the bank president, told a conference of development activists at the bank's annual conference in Prague that he was warned against tackling corruption in client countries when he took over the presidency in 1995.