Updated to include response from Sen. Majority Leader Harry Reid, D-Nev.

Senate Democrats are blocking a move to attach federal jobless benefits to a tax cut bill.

Sen. Dean Heller, the Nevada Republican who co-authored legislation to revive expired unemployment benefits with retroactive pay, said Democrats rejected his effort to include it in the tax cut package, which is set for a vote as early as next week.

“That’s not going to happen,” Heller told the Washington Examiner. “There just isn’t the appetite I had expected on the Left to address the issue.”

Heller pointed out that Senate Democrats, who are in the majority, have not allowed a tax bill to be amended in three years.

“I’ve been told we are not going to this time, either.”

Democrats for months have been attacking House Republicans over their refusal to take up an extension of federal jobless pay.

Senate Majority Leader Harry Reid, D-Nev., even blamed the wealthy Koch brothers, who fund a conservative political action committee that helps Republican candidates.

“Charles and David Koch aren't concerned with the long-term unemployed families,” Reid said in a recent Senate floor speech. “And so the Republicans that they sponsor in the House of Representatives are content to do nothing for the long-term unemployed.”

A Reid spokesperson told the Examiner that Heller has not offered his amendment and no final decision has been made.

“Nothing has been ruled out on the extenders bill, but anyone who wants to pass UI should be focused on pressuring Speaker Boehner, who has the Senate-passed bill sitting in his lap,” spokeman Adam Jentleson said.

Senate Democrats said earlier this year they plan to use a series of bills Republicans oppose, including jobless pay and a minimum wage increase, to contrast the two parties ahead of the November election.

The Senate passed Heller's bill to extend jobless pay in April.

It revives benefits that expired in December for the nearly 3 million long-term unemployed. The bill would also provide retroactive benefits from the December expiration.

House Speaker John Boehner rejected the bill because it does not include job-creating measures. The Ohio Republican said the bill would make it impossible to prevent fraud because state officials would have difficulty determining who is actually eligible for back pay.

If Heller was successful in attaching the jobless benefits measure to the Senate tax bill, it may have helped its chances in the House, because Republicans want the tax cut extensions to eventually pass.

With that option now off the table, Heller said he is searching for a way to attach the jobless pay measure to another bill.

“They haven’t lost the enthusiasm on the issue,” Heller said of the Senate Democrats. “They just think this isn’t the vehicle by which to get it done.”