Arno Halusa, 67, a career diplomat who served as Austrian ambassador to the United States from 1972 through 1976, died of pneumonia Tuesday in Vienna, Austria.

He retired from the Austrian foreign service after completing his tour in Washington, and became secretary-general of the Austrian Federation of Private Industralists.

Mr. Halusa was born in Lans, Tirol, Austria. He entered the Austrian foreign service in 1934 after receiving a law degree from the University of Vienna.

He served from 1935 to 1938 as a vice consul in New York. After the Nazi invasion of Austria in 1938, he was sent first to the German legation in Quito, Ecuador, and then to the German legation in Bangkok, Thailand.

Mr. Halusa returned to Austria after World War II. He later represented his country at diplomatic posts in Romania, France, Spain and Portugal.

In 1953-54, he was deputy director for political affairs and then director of the general secretariat of the Austrian Ministry for Foreign Affairs. During this period the groundwork was laid for the 1955 treaty with major powers that gave Austria, which had been reestablished in 1948 as a republic under Allied occupation, its full independence and neutrality.

After serving as envoy to Thailand, Indonesia, the Philippines and Cambodia, Mr. Halusa became Austria's ambassador to India in 1958, serving four years. He was his country's ambassador to the Organization of European Cooperation and Development (OECD) in Paris during 1964-68.

He had served frequently as a delegate to the General Assembly of the United Nations and to numerous other conferences. While ambassador here, he had delivered many lectures on world affairs in various parts of the country.

He is survived by his wife, the former Constance Monro, and a son, Martin, of Vienna; a daughter, Ruth Mayrhofer-Gruenbuehel, of New York; his mother, Marie Haulusa, and a sister, Edith Halusa, both of Vienna, and three grandchildren. CAPTION: Picture, ARNO HALUSA