PITTSBURGH, March 31 (Reuters) - U.S. Treasury Secretary Timothy Geithner expressed confidence on Wednesday that China will decide it is in its interest to make its yuan currency more flexible, but did not say when that might happen.

I am very confident that they are going to decide it is in their interest to move on currency reforms, Geithner told reporters after touring a steel plant and meeting with steel executives and union leaders.

It's very important that they take the steps they said they would take to allow their currency to move to a more flexible system, Geithner added in response to a question on China's exchange rate policy.. (Reporting by Corbett B. Daly; Editing by Leslie Adler)