President Obama told congressional leaders late Friday that he intends to give federal employees a 1 percent pay raise starting Jan. 1 because Congress has taken no action on the issue.

Obama had announced in his budget plan in April that he wanted to end a nearly three-year pay freeze for the federal workforce. But since Congress has not passed a spending plan for fiscal 2014, the president is required by the end of August to come up with an “alternative pay plan” to avoid a legal trigger that would automatically raise federal pay in line with private-sector salaries. That trigger could, in theory, give federal workers a raise of about 34 percent.

The president’s default action, however, is not the final word on a raise. Any law Congress enacts before the end of this year that sets a different figure or continues the freeze would override Friday’s order.

In a letter to House and Senate leaders, Obama said civilian federal employees “have already made significant sacrifices as a result of a three-year pay freeze.”

“As our country continues to recover from serious economic conditions affecting the general welfare, however, we must maintain efforts to keep our Nation on a sustainable fiscal course.”

Union leaders praised the order as a welcome effort to restore the practice of paying federal employees an annual raise.

“Although the one percent is a pitiful amount that doesn’t begin to compensate for the furloughs and three years of frozen pay, it is a welcome development,” J. David Cox, president of the American Federation of Government Employees, said in a statement.

A temporary spending agreement for most agencies is silent on a raise. Appropriations for other agencies left room for one, but require them to rein in their spending to compensate for the additional cost. The exception is the Defense Department; a Senate committee approved a funding bill this month that includes a 1 percent increase for civilian and military personnel, as recommended by the White House.

Unlike in recent years, the House has not voted to deny a raise this year.

Obama, bowing to budget constraints and political pressure, announced in 2010 that pay rates for federal employees would be frozen for 2011 and 2012. Congress then passed a law initiating the freeze and has continued it this year.

Some employees, however, have received raises with promotions, performance rewards or as they advance up the steps of their pay grades. The House has voted several times to extend the pay freeze by a year or more, with the White House objecting.

Almost half the federal workforce has been furloughed in recent months following the budget cuts known as sequestration, reducing their salaries.