BERLIN (MNI) - Swiss National Bank President Jean-Pierre Roth on Tuesday said the impression is gaining ground that an exit from stimulus measures must take place soon, but the difficulty remains to find the right moment.

"For several months we have been observing signs of an economic recovery and the impression is growing that the crisis measures must soon be corrected in order to preserve price stability over the medium term," Roth said in a speech text for delivery in Geneva.

"The difficulty is to define the appropriate moment to undertake that U-turn," he acknowledged.

At the end of a recession, central banks are always faced with two risks, Roth explained. If they withdraw stimulus too fast, a self-sustaining upswing might be aborted. However, if they wait too long they might be faced with inflation problems in the next 18 to 24 months.

"The current situation has nothing original except for the magnitude of liquidity created and the brutality of the economic accident which took place in autumn of 2008," Roth remarked.

In other comments, the SNB president argued against enlarging the mandate of central banks to assure financial stability. "In reality, one can hardly conceive that the interest rate will target anything but the control of inflation," he contended.

Roth also spoke out against the idea of integrating banking supervision fully into central banks. "An institutional merger will lead automatically to a larger involvement of politics in central bank affairs, which is not automatically good for monetary stability in the longer run," he warned.