Washington (CNN) Threatening the GOP's top priority of passing major tax reform, Republican Rep. Tom MacArthur warned Tuesday night that so many House Republicans are frustrated with plans to nix a popular deduction, they could block the budget this week.

"I haven't done a whip count, but yes, I think there's enough," the New Jersey congressman told reporters.

Meanwhile, Republican leaders, who can afford to lose only 22 members of their caucus, are scrambling to find a solution that would get enough Republicans on board to move forward with the budget, which is considered the first step in tax reform.

The Republican tax reform framework proposes eliminating the State and Local Tax deduction (SALT), a popular tax break that affects nearly one-third of filers, letting them deduct levies like state income taxes and property taxes. It's been in place since the birth of the federal income tax in 1913.

About 30 GOP members represent districts that heavily rely on the deduction, and if they stick together they could derail the resolution.

Read More