The House Ways and Means Committee voted yesterday to slash benefits for future Social Security disability retirees by an average 15 percent, in order to discourage malingering and save an estimated $1 billion a year by 1984.

Critics of the $15 billion-a-year disability program said high benefits-sometimes higher for the family of a disabled worker than his average earnings before being disabled-encourage some workers to sneak onto the rolls even when not totally disbaled, and discouraged them from seeking rehabilitation.

Basically, the program benefits workers too young to retire but too disabled to work at any job.

Benefits can exceed prior average earnings in some cases when a disabled worker gets extra monthly payments for a dependent wife and child.

The committee's bill goes next to the House floor, then to the Senate.

As approved yesterday with Carter administration support, the bill clamps a ceiling on total monthly family benefits. The ceiling is 80 percent of the worker's average monthly earnings before becoming ill. It further provides that total family benefits won't exceed 1 1/2 times the sick worker's primary monthly payment. It also reduces the number of low-earning years that may be "dropped out" when calculating the average salary on which benefits are based.

The ceilings would apply only to those going on the disability rolls after Jan. 1, 1980. Workers already onthe rolls won't be affected. The Congress ready on the rolls won't be affected. The Congressional Budget Office estimated that the average annual family benefit for average-salary male workers would be $7,730 im 1980 under the bill, compared with $9,070 under current law. The average-salary worker would be one who made $12,000 a year before disability.

To encourage workers who are receiving disability benefits to try working, the bill makes several liberalizing changes. It allows those who try to work, but then fail, to go back on disability more easily. It reduces a second two-year waiting period for Medicare benefits for those who leave the rolls and return. And it provides for tightening administration of the program.

In 1980, it wouldn't save any money, but by 1984 the saving to the Social Security disability fund would be over $1 billion as more and more newcomers entered the reduced benefit rolls.

A move to slash benefits still further lost, 16 to 14, and an amendment to tighten the already tough definition of disability lost, 13 to 12.