MEXICO CITY, Dec 11 (Reuters) - A senior lawmaker in Mexico’s ruling party on Friday urged the lower house of Congress to suspend debate until next year on a controversial financial bill that has sparked stiff resistance from the central bank as an attack on its autonomy. Mexico’s Senate on Wednesday passed the draft legislation that would make the Bank of Mexico (Banxico) buy up cash that commercial banks cannot return to the financial system. The Senate’s approval of the law, which was pitched by President Andres Manuel Lopez Obrador’s ruling National Regeneration Movement (MORENA), met with strong pushback from the central bank due to the apparent risks it harbors. Advocates of the law say it will help poor migrant families disadvantaged by the financial system to unload their cash. But critics say it could end up forcing Banxico to absorb money from drug gangs and make it a target of international authorities. Congressman Alfonso Ramirez Cuellar, a former head of the lower house budget committee and former party chairman of MORENA, said the bill was too important to be rushed through Congress. To that end, Ramirez said he was proposing that debate on the bill be postponed until Congress reconvenes in February. Congress is due to enter winter recess on Dec. 15. “Congress must safeguard the Bank of Mexico’s faculties and avoid the risk of contaminating the foreign exchange system,” he wrote on Twitter, calling for national debate on the issue. (Reporting by Dave Graham and Stefanie Eschenbacher; editing by Jonathan Oatis)