While Treasury Secretary Jack Lew said the Treasury Department was looking to see what it could do to stem the tide of corporate tax inversions, Rep. Chris Van Hollen, D-Md., told CNBC on Monday that the "whole issue" can only be addressed in legislation.
"I do hope the White House will take whatever action they can using executive authority to reduce the value and benefits of these inversions until Congress acts," Van Hollen said in an interview with "Closing Bell."
Earlier Monday, Lew reiterated his call for legislative action to stop corporate inversion deals, where U.S.-based companies merge with a foreign competitor and then restructure and relocate tax domiciles to the lower-tax country. However, Lew said his office is investigating what it could do to help.
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"Congress may not move as quickly as necessary to respond to the growing wave of inversions. Given that, the Treasury Department is completing an evaluation of what we can do to make these deals less economically appealing, and we plan to make a decision in the very near future," Lew said in a speech at the Urban Institute, a Washington think tank.
Van Hollen, co-sponsor of the "Stop Corporate Inversions Act of 2014," blasted his Republican colleagues for their lack of political will to pass an anti-inversion bill.
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"Why should we sit around while people are using this tax avoidance scheme?" he asked. "Congress is able to take action if it had the will, to address this issue in a serious way."
As for those who say corporate tax reform is the real issue, Van Hollen said he's all for reform but that inversions should not be ignored.
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"Saying you have to do tax reform before you address this hemorrhaging of the tax base through inversions is just an excuse for doing nothing," he said.
—By CNBC's Michelle Fox