The Washington Area Construction Industry Task Force has filed suit in U.S. District Court, accusing the federal government of failing to enforce a plan to eliminate racial discrimination in the construction industry.

The task force, a coalition of local building trade and civil rights groups, asks the court to order the government to enforce the plan.

Under federal contact compliance laws, construction companies working on federal or federally assisted projects are required to set up affirmative action plans to achieve equal employment opportunity for minorities - or face the loss of their government contracts.

The suit names as defendants the Department of Health, Edutation and Welfare, the Department of Defense, the Environmental Protection Agency, the General Services Administration, the Department of Labor and the Office of Federal Contract Compliance.

A task force spokesman said that the percentage of minority union journeymen in the skilled contruction trades here has risen only 1 per cent since 1970, from 17.4 to 18.4, "The percentages among nonunion workers are probably better, but it is harder for them to get jobs and the pay is lower . . . It is the unions that provide the basic labor pool."

The task force contends that the agencies apparently have rarely used their "lever" - the cancellation of contracts - even against construction firms that have failed to meet the requirements over a period of months or years, the spokesman said, adding that the task force expects to obtain better data on the subject as a result of its lawsuit.