Senior World Bank officials have been holding a key board meeting in which they were to discuss the fate of the organisation's chief, Paul Wolfowitz.
Mr Wolfowitz has said he regrets his mistake
Mr Wolfowitz has been under pressure to quit after admitting helping his partner win a promotion and pay rise.
Although the US continues to support Mr Wolfowitz other nations have questioned his position.
Mr Wolfowitz is due to appear before the press after the meeting for the first time since the controversy broke.
British Development Minister Hilary Benn expressed regret that the question of Mr Wolfowitz's fate would overshadow the joint meeting of the IMF and World Bank in Washington.
He said the incident had "damaged the bank" and should never have occurred.
Germany's development minister said Mr Wolfowitz should ask himself whether he was still able to continue in his role.
"At this point it is my conclusion that he has to decide for himself whether in regard to this mistake he can credibly fulfil his duties," Heidemarie Wieczorek-Zeul said.
Sunday's news conference in Washington will come at the end of the three-day meeting of G7 finance heads, the World Bank and the International Monetary Fund.
A controversial nominee to the role from the beginning due to his part in driving forward the war in Iraq, Mr Wolfowitz has been a divisive figure during his two years at the bank, analysts say.
Shortly after he took on the job, his girlfriend, Libyan-born Shaha Riza, was seconded to the US state department to avoid creating a conflict of interest.
But rapid rises in her tax-free World Bank salary to about $193,000 (£97,000) - more than the $186,000 Secretary of State Condoleezza Rice receives before tax - raised questions about his involvement in the transfer.
The bank's staff association is leading the call for his resignation, saying he should "act honourably and resign" as he had "destroyed" the trust of the international lending agency's employees.
Mr Wolfowitz has apologised for his mistake and, in a World Bank memo published by Associated Press, he expressed his "deep unhappiness" at becoming involved in her case.
Documents released by the bank also show that Ms Riza said she was forced to leave her job because of her close relationship with the bank's chief.
"I have now been victimised for agreeing to an arrangement that I have objected to and that I did not believe from the outset was in my best interest," she said in a note to the World Bank board.
The BBC's Justin Webb in Washington says Mr Wolfowitz is hanging on, but his position is looking very weak, with the White House the only player coming out squarely in his favour.
The case has caused huge embarrassment to Mr Wolfowitz, who has campaigned against corruption and for sound governance since he was appointed head of the bank in 2005.