House Budget Committee chair Rep. Tom Price (R-Ga.) speaks during a meeting. (Allison Shelley/Getty Images)

A correction to the House Republican budget released this week could mean far deeper cuts for federal employees than the original document suggested, further alarming government workers and their unions already upset about hits they have taken in recent years.

The initial version called for the House Oversight and Government Reform Committee to identify $100 million in savings over a decade from mandatory spending programs within its jurisdiction, which includes the federal-worker retirement and health plans. But the amount was supposed to be $1 billion — 10 times larger than first advertised.

A drafting error caused the mistake, according to the ­Republican-controlled House Budget Committee, which corrected the figure during a markup of the legislation Wednesday.

Federal-employee representatives, who had expressed concerns about the lower $100 million figure, renewed their criticism of the Republican budget proposal Thursday.

National Treasury Employees Union President Colleen M. Kelley said federal workers have already contributed $159 billion toward deficit reduction during the Obama administration since 2010 and shouldn’t have to sacrifice more.

“Once again, federal employees are being targeted disproportionately for budget savings because they chose to serve their country,” Kelley said.

Similarly, American Federation of Government Employees President J. David Cox said that “the real mistake [with the Republican budget] is robbing federal workers of their hard-earned pay and benefits in the first place.”

“Regardless of whether it’s $100 million or $1 billion, any proposal to impose further cuts on federal employees is a slap in the face to America’s workers,” Cox added.

House Oversight Committee spokeswoman Melissa Subbotin said that the Republican side of the panel has not yet decided how to reach the savings target but that its members are “diligently working through a key list of programs and expenditures.”

The House budget proposal also would require federal employees, lawmakers and congressional staffers to contribute more toward their retirement plans.

The budget resolution does not mention a specific amount, but it refers to the 2010 Simpson-Bowles recommendations, which called for the government and its workforce to contribute an equal share toward the cost of the benefit.

Under that plan, federal employees’ contributions would increase to 6 percent of their salaries. Their rates are currently between 0.8 percent and 4.4 percent of pay, depending on when they were hired.

Overall, the House GOP budget would cut federal spending by $5 trillion over a decade. Republicans say it would prevent deficit spending and create a surplus by 2024.

President Obama’s 2016 budget proposal, released in January, would reduce future deficits without eliminating them altogether. The plan would save $1.2 trillion over 10 years, according to an analysis from the nonpartisan Congressional Budget Office.

The CBO said Monday that the federal deficit would drop slightly this year to $468 billion, representing the smallest amount as a portion of the economy — 2.6 percent of gross domestic product — since 2007. But the office also projected a deficit increase after 2018 and warned of dangerously high-interest payments and deficits in the long term.