While the comment in a live CNBC television interview stopped short of a formal endorsement of the former French finance minister's candidacy, it appeared to be a strong signal that Washington, which holds a blocking vote in the IMF, wants her to stay.

"I have a very close working relationship with Christine Lagarde," Lew said. "I have the highest regard for her. I think she's done a great job. I look forward to continuing working with her."

A judge last month ordered Lagarde, whose first term expires on July 16, to stand trial in France over alleged favours for a businessman ally of then President Nicolas Sarkozy while she was finance minister. Lagarde has said she will appeal against the judge's order and no date has been set for the trial.

(Writing by Paul Taylor; Editing by Dominic Evans)