Key Republican senators say they are close to a deal on a budget bill that is to serve as the legislative vehicle for a possible $1.5 trillion tax cut.

"I think there is" a deal, said Sen. Bob Corker, R-Tenn. He did not deny reports of a minimum $1.5 trillion tax cut provision, and said, "There is just one number."

Corker said an announcement is imminent, but no vote has been scheduled on the budget package in committee and some Republicans on the panel are reluctant to vote on a measure.

"While each member of the caucus will have to make their own decision, I believe our agreement gives the tax writing committees enough headroom to achieve real tax reform that eliminates loopholes and lowers tax rates for hardworking Americans," Corker said late Tuesday. "I will be watching closely as the tax reform legislation is drafted, and ultimately, my support will be contingent on a final package that generates significant economic growth and does not worsen but hopefully improves our fiscal situation."

Corker has been working with Sen. Pat Toomey, R-Pa., on a budget agreement with the help of Senate Majority Leader Mitch McConnell, R-Ky. Both Corker and Toomey are members of the Budget Committee.

The Senate's GOP Conference Committee Chairman, John Thune, of South Dakota, confirmed a deal is close.

"What they have been trying to do is get an agreement at the budget committee level about instructions that they can send to the Finance Committee that give us maximum flexibility to write a bill that creates economic growth and creates wages," Thune said.

Republicans believe tax cuts will spur the economy and job creation.

More details of the plan weren't clear, but President Trump has suggested that the wealthy may end up paying more under the GOP tax plan and has said it's important to lower taxes on the middle class.

But the tax cuts will not be offset, meaning the cuts will add to the deficit, at least on paper, because economic growth will not factored in. The GOP believes the tax cuts will expand the economy and ultimately shrink the deficit.

"Most of our members are willing to accept a certain amount of deficit," Thune said, adding that a few tax cut numbers are under consideration.

Under the Senate rules, the legislation cannot add to the long-term deficit if it is to pass under reconciliation rules that allow a bill to advance with just 51 votes. That means the tax cuts may have to be temporary, much like the Bush-era tax cuts.

McConnell on Tuesday did not specifically promise a vote on a budget but said tax reform, which requires the budget legislation in order to circumvent a Democratic filibuster, would be completed soon by Republicans.

Senate Republicans may first attempt to repeal and replace Obamacare this month, ahead of a Sept. 30 deadline.

"The next big priority is tax reform and I think we'll be fine," McConnell said.

Thune said the Corker-Toomey agreement signals major progress on a tax reform deal.

"Corker and Toomey represent the far ends of the spectrum of our conference on what they want to see that look like," Thune said "The fact that they are coming together leads me to believe we are close to getting a budget that they can report out of committee and we can get onto the floor."