Pressure increased on World Bank president Paul Wolfowitz yesterday after Germany's development minister called openly for his resignation.

Heidemarie Wieczorek-Zeul told the Financial Times Deutschlandthat the bank president's handling of the promotion and salary increase awarded to his companion, Shaha Riza, had made his position untenable.

"The situation, as it is, is no longer acceptable. My conclusion is that Wolfowitz should do the bank a service and take the consequences himself. The sooner, the better," she said.

A spokesman for German chancellor Angela Merkel said Berlin had "full confidence that the World Bank would find a solution that corresponds to its high principles."

Earlier, more than 40 former World Bank officials signed an open letter calling on Mr Wolfowitz to go, declaring that he could no longer act as an effective leader of the institution.

"He has lost the trust and respect of bank staff at all levels, provoked a rift among senior managers, developed tense relations with the board, damaged his own credibility on good governance - his flagship issue - and alienated some key shareholders at a time when their support is essential for a successful replenishment of the resources needed to help the poorest countries, especially in Africa," the former ban k officials said.

The Financial Times reported yesterday that an independent evaluation group that has investigated Mr Wolfowitz on behalf of the bank's board had concluded that he has damaged the institution's credibility.

"The recent chain of events raises concerns in these respects. Indications are that the ability of staff - particularly those working in client countries - to carry out daily interactions with clients, as well as the institution's ability in convening partners, is eroding. Trust is being damaged," the group said in a memo, according to the paper.

Documents released in the past couple of weeks showed that Mr Wolfowitz had a direct hand in securing a US State Department job for Ms Riza in September 2005 that pays her $193,590.

Prior to her transfer, Ms Riza was earning close to $133,000 as a communications adviser in the bank's Middle East department.

Mr Wolfowitz, who has admitted he made a mistake and has apologised, said he got involved in Ms Riza's job transfer shortly after he took the helm with the hope of avoiding a conflict of interest.

Mr Wolfowitz has hired Robert Bennett, a prominent New York lawyer, to help him as he battles to keep his job.

"I've reviewed all the material - all the relevant material - and it is absolutely clear to me that he acted in total good faith in this," Mr Bennett said.