VENICE, July 11 (Reuters) - U.S. Treasury Secretary Janet Yellen said on Sunday that a new mechanism to allow more countries to tax large, highly profitable multinational firms may not be ready for consideration by lawmakers until the spring of 2022. Yellen told a news conference after a G20 finance leaders meeting in Venice in Italy that the OECD “Pillar 1” re-allocation of taxing rights was on a “slower track” than a global corporate minimum tax of at least 15% as part of a major tax deal among 132 countries. (Reporting by David Lawder and Gavin Jones; Editing by Hugh Lawson)