Janet Yellen, President Barack Obama's nominee to lead the U.S. Federal Reserve, is sworn in to testify at her U.S. Senate Banking Committee confirmation hearing in Washington November 14, 2013. Jason Reed/Reuters Federal Reserve Chair Janet Yellen doesn’t like to chime in on matters related to Congressional legislation.

But now that she knows her days as head of the US central bank are probably numbered, she is not proving shy about defending the post-crisis Wall Street regulations that she and her colleagues have spent so long debating and implementing.

US President Donald Trump has vowed to rip up Dodd-Frank financial reforms implemented after the deepest crisis in modern history. He recently cited his friends’ inability to get loans as a key reason for removing the rules.

In testimony before the Senate Banking Committee on February 14, Democrats asked Yellen whether US President Donald Trump and his fellow Republicans’ claim that the new rules were hurting lending and growth had any merit.

She was unequivocal, pointing to a survey of small businesses that shows just 4% are having trouble getting credit.

"Lending has expanded overall by the banking system, and also to small businesses," she said. "US banks are generally considered quite strong relative to their counterparts. They've built up quite a bit of capital, partly as a result of our insistence that they do so."

More broadly, she pushed back against the notion that the new rules had encumbered the economy, arguing instead that they have made the financial system safer and Americans more confident.

"We lived through a devastating financial crisis. Most members of Congress and the public came away from that experience feeling that it was important to take a set of steps that would result in a safer and stronger financial system," she said. "I feel that we have done that."