More than one-third of all U.S. military personnel reported some loss of productivity on the job last year because of alcohol consumption, according to a Pentagon survey released yesterday.

The study of almost 22,000 servicemen and women around the world showed that drinking problems have increased significantly during the past two years, while use of narcotics has declined.

One in eight of those responding to the voluntary questionnaire said they drink eight or more beers or hard alcoholic drinks per day at least once a week. And 18 percent of all military personnel experienced one or more "serious consequences" of alcohol use, such as illness, arrest or broken marriages, during the past year.

"Military personnel in the four services around the world," the report concluded, "consumed considerable amounts of beer, wine and hard liquor."

The survey, the second in what the Defense Department plans as a regular biennial examination, did contain some good news for the Pentagon. The percentage of those using naroctics, including marijuana, dropped from 27 percent in 1980 to 19 percent in 1982.

The decline in marijuana use was most noticeable among the lower ranks of enlisted men, particularly in the Navy and Marine Corps, which have been waging a well-publicized campaign against narotics abuse at sea. While 48 percent of enlisted sailors reported some narcotics use in a typical month in 1980, only 21 percent of the same group had used narcotics during the past 30 days when the questionnaire was administered in 1982.

There was little good news about alcohol, however. The survey showed why Defense Secretary Caspar W. Weinberger signed a directive two weeks ago cracking down on drunk drivers in the military.

"Overall, military personnel in 1982 were significantly more likely to have become drunk, to have stayed drunk or to have experienced one or more consequences of their drinking," the report said.

Fifteen percent of those responding to the survey said they had been drunk or high on the job during the past year. Thirty percent reported "lowered performance" at work because of alcohol and 20 percent came late, left early or missed work because of a drinking problem.

The study lumped those problems together to conclude that 34 percent of all military personnel suffered some alcohol-related productivity loss. Among lower-ranking enlisted men, including privates and some sergeants and petty officers, the proportion was greater than 40 percent.

Nine percent of those responding to the survey, and 12 percent of the lower ranks, considered themselves dependent on alcohol.