Sen. Elizabeth Warren has "opened up the opportunity" for Congress to seriously think about breaking up Facebook, Democratic Rep. Maxine Waters told CNBC on Wednesday.

"The discussion now is in the air," the congresswoman and chair of the House Financial Services Committee said on "Closing Bell" shortly after Facebook CEO Mark Zuckerberg's testimony before the committee.

Warren, a front-runner in the 2020 presidential race, has vowed to break up Google parent Alphabet, Facebook and Amazon if elected. Warren says companies such as Facebook have engaged in monopolistic or "anti-competitive" practices and the government has a responsibility to break them up.

On Wednesday, Waters and other lawmakers grilled Zuckerberg over the company's policies, including its track record on diversity, the cryptocurrency it plans to create with its organization Libra, and attempts to prevent misinformation.

Waters, who is urging Facebook to halt its plans to launch its cryptocurrency, suggested at the hearing that the social media company has become too powerful and raised the possibility of breaking up the company.

When asked on CNBC whether the committee would take regulatory action against Facebook and other tech companies, Waters said, "We have a lot of work to do."

"In addition to learning more about Libra and how it is organized, we will be talking with the regulators, some of whom have set up advisory committees to talk about what they know," Waters said.

She continued: "When all of this work is done, I think there will be decisions made on whether or not we have enough in law to deal with oversight, whether we need legislation or what needs to be done."