President Carter's federal pay reform package contains language that would make the birthday of Martin Luther King Jr. (Jan. 15) a national holiday.

Altough the compensation package is viewed by many civil servants as a blueprint for cutting federal pay and fringe benefits, it would create the new holiday to honor the slain civil rights leader. The extra day off would be granted automatically to 1.2 million white collar and blue collar government employes. It would not cover postal workers, who would have to bargain separately with the mail-moving corporation for the extra day off.

If approved by Congress the new holiday would be the 10th for U.S. workers. (Washington area civil servants get a bonus holiday every four years on Inauguration Day.)

Various bills have been introduced in the past few years to honor the late Dr. King, but this is the first time a president formally has proposed it in legislative form. Politically it will be hard to oppose, which is perhaps one reason Carter chose pay reform - a complex and controversial subject - to accomplish it. The pay reform bill would link federal pay and fringes to industry levels. It would adjust government pay in as many as 100 localities based on the going rate paid private industry workers in similar jobs.

Ironically, the extra holiday probably would have the effect of shaving government catchup-with-industry raises. The extra government holiday would increase the value of the federal fringe package when compared to industry benefits. Private industry does not uniformly follow federal holidays. Some firms remain open on holidays such as Washington's Birthday, Memorial Day and Veterans Day.