A top Federal Reserve official said Wednesday that the main idea behind House Republicans’ proposed alternative to the 2010 Dodd-Frank financial reform law would fall short of ensuring the financial system’s safety.

Speaking in Washington, Gov. Daniel Tarullo took aim at the plan advanced by House Financial Services Committee chairman Jeb Hensarling to offer banks the ability to opt out of numerous regulations under the law if they maintain a 10 percent capital ratio, based on a very broad measure of capital.