Washington - International Monetary Fund (IMF) chief Dominique Strauss-Kahn has reportedly apologized to staff over an improper affair with a married subordinate.

Meanwhile, the IMF on Monday said an inquiry into whether he abused his position will be completed by the end of the month.

Strauss-Kahn met Friday with the IMF's executive board, which has the power to dismiss him, and has been "fully supportive" of the investigation, according to a statement from Shakour Shaalan, who leads the 24-member board.

An outside law firm has been hired to conduct the investigation and should be finished by the end of October, said Shaalan, who represents Egypt and other Arab countries on the board.

"Both (Strauss-Kahn) and directors agreed that it is in the best interests of the fund and its 185 member countries for this inquiry to be thorough, independent and completed expeditiously," Shaalan said.

Strauss-Kahn, 59, was named last year as the IMF's managing director. The former finance minister of France is married to French television journalist Anne Sinclair.

The Wall Street Journal, which first reported the story Saturday, said that Strauss-Kahn sent an email to staff apologizing for "an incident concerning me and a staff member."

Strauss-Kahn admitted an "error of judgement" but denied having abused his power.

The IMF investigation concerns his alleged relationship with Hungarian-raised Piroska Nagy, who was a senior official in the IMF's Africa department and now works for the European Bank for Reconstruction and Development in London.

The controversy comes as the IMF is ramping up its efforts to quell a financial crisis that has spread from wealthy to developing nations. During annual meetings earlier this month, the IMF sped up procedures to provide emergency loans to poor countries.

The probe follows last year's resignation by Paul Wolfowitz as head of the IMF's sister organization, the World Bank. A former confidant of President George W Bush, Wolfowitz's was forced out after allegedly securing a promotion outside of the agency for his longtime girlfriend, a World Bank employee.

In Strauss-Kahn's case, the investigation is focussed on the severance package Nagy received when she left the IMF in August, the Journal reported. (dpa)