The Club for Growth was critical of selected portions of the tax bill saying they "fail the pro-growth test," according to The Hill.
"While the corporate tax cut will lead to some increase in our nation's GDP, the rest of the provisions on individual taxpayers fails the pro-growth test," Club for Growth President David McIntosh said
"Republicans must correct at least four serious shortcomings of the House bill to follow through on campaign promises and to bring our nation closer to a tax reform proposal that is truly pro-growth."
Club for Growth has come out against creating a fourth tax bracket for the wealthy, a marginal tax rate for couples on earnings above $1.2 million, a tax reduction on earnings for pass-through businesses and an expiration of the estate tax after six years, The Hill reported.
"All in all, this bill must be changed if Republicans intend to keep their promise of real pro-growth, job-creating tax cuts," McIntosh said.
Despite its concerns, the Club for Growth is expected to be heavily involved in the push for tax reform, the Washington Examiner reported.
Rachael Slobodien, a spokeswoman for Club for Growth said the free-market group will "definitely be continuing to be engaged on the issue" of tax reform.