A federal workers union said Thursday that President Trump's proposed 1.9 percent pay increase for 2018 shortchanges government workers by half of 1 percent.

Trump intends to raise federal employees' wages by 1.4 percent across the board plus locality pay increases, which would average 0.5 percent.

"NTEU believes this figure is too low especially in light of the fact that federal law calls for a 1.9 percent across-the-board raise and private sector wages are growing at an even faster rate," Tony Reardon, national president of the National Treasury Employees Union, said in a statement. "Add to that, current proposals attacking the federal retirement system would result in a pay cut for federal workers."

In his letter, Trump said he believes the annual raise "will not materially affect our ability to attract and retain a well-qualified Federal workforce."

Trump also announced a 2.1 percent monthly pay increase in 2018 for members of the military.

The White House announced its proposed pay raises Thursday, the last day to do so. In previous years, the administration has rolled out its plan days in advance.

Congress could introduce appropriations legislation that would set the federal pay raise amounts in 2018, replacing Trump's plan, but there currently is no palpable motion in the House or Senate to do so.

NTEU also decried former President Barack Obama's proposed 1.6 percent pay increase for 2017.

In February 2016, NTEU said the increase was "too low and does little to overcome several years of pay freezes and below-market increases."

Obama issued an executive order in December mandating a 2.1 percent increase for federal workers in 2017. The amount mirrored the raise military personnel were set to receive that year.

Obama gave federal employees a 1.3 percent raise for 2016.