Mr Wolfowitz says he is being treated unfairly

In a letter, a group of 32 officials warned that the scandal was undermining the bank's credibility.

The letter also called for a clear and decisive action to be taken.

Mr Wolfowitz is facing calls to resign after it emerged he had ordered a large pay increase and promotions for his girlfriend, who was a member of staff.

The letter - signed by the officials involved in the World Bank's anti-corruption strategy - is the clearest sign yet the controversy over Paul Wolfowitz is affecting its operations around the globe.

"The credibility of our front line staff is eroding in the face of legitimate questions from our clients about the bank's ability to 'practice what it preaches' o­n governance," it says.

The letter was addressed to Mr Wolfowitz and the bank's executive board.

Meanwhile, Mr Wolfowitz has hired a top lawyer and written to the executive board considering his future, accusing it of treating him shabbily and unfairly.

"It is important not o­nly for me but for the institution, that this matter not be resolved by a rush to judgment. That would o­nly compound the damage to all concerned," he said.