U.S. Treasury Secretary Jacob J. Lew pushed back against Republican efforts to curtail the work of a council of regulators charged with preventing another financial crisis and said a failure to examine potential risks could lead to “large-scale problems.”

“If we avoid or are discouraged from asking questions” altogether, “our financial system will be more exposed to unseen risks, potentially leading to large-scale problems,” Lew said in testimony prepared for a hearing Tuesday before the House Committee on Financial Services.

Lew also said regulators should take further action to reduce vulnerabilities in wholesale funding markets, including money market-mutual funds and triparty repurchase agreements, “that can lead to destabilizing fire sales” of assets.

He said cybersecurity threats “remain a top priority” for the risk council, and that U.S. regulators should continue to work with overseas counterparts to address concerns about benchmark reference rates such as the London Interbank Offered Rate, or LIBOR.

Created by the 2010 Dodd-Frank law, the Financial Stability Oversight Council is authorized to designate non-bank financial companies as systemically important and subject them to Federal Reserve oversight. Under Dodd-Frank, bank-holding companies with more than $50 billion in assets are overseen by the Fed.

After American International Group Inc., Prudential Financial Inc. and General Electric Co.’s finance were named, Rep. Randy Neugebauer of Texas, a Republican, introduced a bill seeking a one-year moratorium on further designations. Another bill, sponsored by Rep. Scott Garrett, a New Jersey Republican, would allow members of Congress into the council’s meetings.

The bills would need Democratic support to pass the Senate.

“The Council shares information about its work with Congress and the public in a clear and transparent manner,” Lew said in the testimony.

“However, much of the Council’s work—particularly in regards to companies under consideration for potential designation—relies on sensitive company and industry data and information that would not be shared by firms or regulators without an expectation of confidentiality.”

As Treasury secretary, Lew is chairman of the council, whose 10 voting members also include the chairmen of the Fed, the Securities and Exchange Commission and the Federal Deposit Insurance Corp.