Washington (CNN) -- Top Senate Republicans unveiled a proposal Thursday to replace looming across-the-board budget cuts, most notably to the Pentagon, with new restrictions on both the compensation to and size of the federal work force.
The mandatory cuts are a consequence of the failure of Congress' so-called super committee in November.
Under an agreement that set up the special joint congressional panel, automatic across-the-board spending cuts of more than $1 trillion will begin in 2013 because the committee was unable to reach agreement on a broad deficit reduction plan.
The Republican proposals offered Thursday would alter the composition of those required cuts for the first year they would take effect in order to spare defense spending.
Specifically, the Republicans want to achieve the required savings by extending a freeze on federal worker pay through June 2014 and reducing the federal work force through attrition. Federal agencies would be allowed to hire only two people for every three retiring or leaving, until the total size of Washington's work force is reduced by 5%.
The Down Payment to Protect National Security Act is backed by GOP Sens. John McCain and Jon Kyl of Arizona, Lindsey Graham of South Carolina, John Cornyn of Texas, Marco Rubio of Florida and Kelly Ayotte of New Hampshire.
"Defense Secretary Leon Panetta has called the cuts to defense spending 'devastating,' likening them to 'shooting ourselves in the head,' " the senators said in a written statement. "The prudent path forward would be to replace all of the across-the-board cuts with an equal amount of responsible savings."
The measure would cut $127 billion from the federal budget, effectively replacing the first year of savings now set to start in 2013.
The senators have long been vocal opponents of the automatic scheduled cuts, formally known as sequestration, and have vowed to find alternatives that would protect the Department of Defense from a new round of spending reductions.
House Armed Services Committee Chairman Buck McKeon, R-California, has introduced a similar bill. McKeon's bill has 42 co-sponsors.
Democrats reacted to the Senate proposal with deep skepticism, saying Republicans should instead agree to compromise on needed deficit reduction steps including increased tax revenue. So far, Republicans have rejected Democratic calls to raise taxes on the wealthy in order to generate more revenue.
White House Press Secretary Jay Carney said Thursday that the new GOP proposals amounted to Congress trying to go back on its word.
The sequester mechanism was intended to force action on a broader deficit reduction deal, Carney said, adding: "Sequester was bad policy for a reason, so that the cuts don't get enacted."
Instead, he said, Republicans were seeking changes a few months later, in effect saying, "Oh, we didn't really mean it. Let's change that."
President Barack Obama "certainly hopes that the Congress will take up the issue again and present him with deficit reduction measures that are balanced in a way that he has outlined and in a way bipartisan deficit reduction commissions have outlined," Carney said.
One Senate Democratic leadership aide, speaking on condition of not being identified, said: "If Republicans wish to avoid the trigger, they should finally get serious about revenues so we can pass the kind of grand bargain the president has proposed."
Obama negotiated unsuccessfully with House Speaker John Boehner, R-Ohio, last year over the terms of a package that reportedly would have saved as much as $4 billion over 10 years.
The failed talks between Obama and Boehner, part of negotiations forced by the need to raise the federal debt ceiling in August 2011, led to the agreement that set up the super committee and the automatic spending cuts if it failed.
The cuts were officially set in motion when the super committee was unable to agree on an additional $1.2 trillion in deficit savings.
CNN's Alan Silverleib contributed to this report.