Five-hundred seventy-five retired U.S. admirals yesterday condemned one of their colleagues, a leading opponent of increased military spending, for criticizing U.S. policies in a television interview broadcast in the Soviet Union.

The admirals, including seven of the eight retired chiefs of naval operations who have led the Navy during the past three decades, attacked retired Rear Adm. Gene R. LaRocque for his "reprehensible" use of Soviet television "to condemn the policies of the United States, his own country." The criticism and 575 signatures, representing a majority of retired active-duty admirals, appeared in an advertisement in The Washington Times.

"An American citizen has responsibilities as a citizen to support his own country," said retired Adm. Thomas H. Moorer, chairman of the Joint Chiefs of Staff from 1970 to 1974 and organizer of yesterday's broadside. "If he doesn't like it over here, perhaps he should go somewhere else."

LaRocque, director of the private Center for Defense Information and one of the most visible critics of Reagan administration military policies, shrugged off the criticism yesterday.

"There are unfortunately some in the United States who believe the Soviets are the enemy who we must defeat by war," La Rocque said. "I think the enemy is nuclear war."

LaRocque also suggested that many of the retired admirals who criticized him are envious of the attention he gets as a dove.

"These old guys are sitting around Coronado or Florida or elsewhere, playing golf and collecting stamps, and they're not involved anymore," LaRocque said. "No one's calling them to go on television shows or radio programs or to fly to Australia."

"Anyone who's jealous of LaRocque," responded Moorer, a senior fellow at Georgetown University's Center for Strategic and International Studies, "is one step away from St. Elizabeths" Hospital.

Soviet television interviewed LaRocque in Washington for a program broadcast in the Soviet Union on June 13. Deputy Secretary of State Kenneth W. Dam was interviewed for the same program, the first time in several years that an interview with a high-ranking U.S. official was shown in the the Soviet Union and his remarks were relayed without Soviet censorship.

Dam used his six minutes of air time to stress what he called the Reagan administration's commitment to arms reduction and its desire for military strength but not superiority. LaRocque then suggested that President Reagan's spending policies show he is more committed to arms buildup than reduction, despite his statements.

"I would say that President Reagan is seriously inclined as far as strategic arms control is concerned, but only so far as this concerns control of Soviet weapons, not of U.S. weapons," LaRocque said on the show.

Moorer said he wrote to 790 retired admirals, all those for whom addresses could be found. Of the retired Navy chiefs of naval operations who have served since 1953, only Adm. Elmo R. Zumwalt Jr. did not sign.