Health-care premiums for most federal employes and retirees will increase in 1982 by an average of 31 percent and coverage will be reduced under new rates and benefits announced yesterday by the Office of Personnel Management.

Some of the most important coverage reductions have come in the popular Blue Cross/Blue Shield plans, which dropped alcohol treatment benefits, for example, restricted abortion payments and limited the number of visits to physicians and psychiatrists.

The new rate and benefit structure takes the place of a schedule announced Dec. 3 by OPM that called for an average premium increase of 40 percent in 1982.

After the Dec. 3 announcement, the U.S. Circuit Court of Appeals here reversed a lower court ruling and allowed OPM to make an additional 6.5 percent reduction in benefits on top of reductions of 6.1 percent that already had been made. The schedule announced yesterday reflects both rounds of cuts and a consequent reduction in how much premiums will rise, according to OPM spokesman Patrick Korten.

The government's health-insurance program covers about 10 million federal employes, retirees and their dependents, including nearly 1 million Washington-area residents.

The total cost for the government and those covered will be $4.9 billion, an increase of $515 million over 1981. The government's share will go up to $2.39 billion, an increase of $400 million over 1981.

Blue Cross/Blue Shield coverage, accounting for roughly 50 percent of federal workers and retirees covered under the various available plans, will increase the employe's monthly premium for the high-option family plan by $24.36 a month and by $7.34 a month for the low-option family plan.

An individual selecting the high-option plan will pay $10.60 more a month and $2.52 for the low-option plan. These premium increases amount to roughly 33 percent for the high-option plan and 47 percent for the low option.

Premiums under the Aetna Life Insurance Co. plan, the second most popular with 12 percent of the coverage, were raised $1.18 a month for the family high-option plan and $4.86 a month for the individual high option. For low-option coverage, the increases are $3.34 a month for the individual and $8.28 for a family. These changes represent increases of 22 percent for the individual high option, 4 percent for the family high option, 48 percent for the individual low option and 51 percent for the family low option.

In addition to the premium increases, many insurance plans have either eliminated some benefits or will require the insured to pay more out of pocket to cover the cost of medical bills.

Blue Cross/Blue Shield is changing its basic surgical-medical services under the high-option plan to require the insured to pay 20 percent of the bill up to a maximum of $1,000 out of pocket for in-hospital surgery, physician care, consultations, physical therapy, X-rays and laboratory services.

The insured under the high-option plan must pay $25 a day for the first 10 days of hospitalization for each admission. Under the low-option plan, the insured will pay $30 a day for the first 10 days.

Some other Blue Cross/Blue Shield changes, in addition to elimination of the alcoholism treatment benefit under both high- and low-option plans:

A limit of 50 visits under the high-option and 25 under the low-option plan has been imposed for all home and office visits with a physician, psychiatrist or analyst in a calendar year.

The basic dental benefits under the high-option plan have eliminated fillings, extractions and other work beyond oral examinations, X-rays and cleaning of teeth.

The deductible for a supplemental, catastrophic provision to protect the insured against heavy out-of-pocket expenditures has been increased under the low-option plan from $2,000 to $2,500.

Under both the Blue Cross/Blue Shield and Aetna plans, coverage for abortions is eliminated except where the life of the mother would be endangered if the fetus were carried to term.