Robert Lowe Kunzig, 63, an associate judge of the U.S. Court of Claims and a former chief of the General Services Administration, died Feb. 21 at Georgetown University Hospital. He had a lung ailment.

Judge Kunzig was appointed to the court by President Richard M. Nixon and took his seat in 1972. From 1969 until 1972, he was administrator of the General Services Administration, the government's housekeeping agency.

A native of Philadelphia, he earned his law degree at the University of Pennsylvania. He served in the Army in Europe during World War II and was a member of the prosecution staff at the Nuremberg war crimes trials after the war.

He practiced law in Philadelphia from 1948 to 1953, when he became counsel to the House Un-American Activities Committee. In 1955, he was named executive director of the Civil Aeronautics Board. In 1958, President Dwight D. Eisenhower appointed him to the U.S. Foreign Claims Settlement Commission.

From 1961 to 1963, Judge Kunzig was a businessman in Minnesota. He returned to Washington in 1963 as administrative assistant to Sen. Hugh Scott (R-Pa.), a post he held until 1967. For the next two years, he was executive director of the General State Authority of Pennsylvania and of the highway, bridge and transportation authorities.

Judge Kunzig, who lived in Washington, was a member of St. John's Episcopal Church and the Metropolitan Club.

His marriage to Pamela Wilson Chappell ended in divorce.

Survivors include a daughter, Kim Stalker of Buffalo, N.Y.; a son, Robert L. Jr., of Fort Lauderdale, Fla., and his father, Dr. Robert Weiss Kunzig, and a sister, Mildred Keil, both of Philadelphia.