Current and proposed Reagan administration budget cuts, which already have removed about 3,000 Washington families from welfare rolls and 4,600 from food stamps, will have a "devastating impact" on the children of needy families nationwide, D.C. Social Services Commissioner Audrey Rowe told a national conference of adoption agency officials yesterday.

"As a nation, we have always proclaimed that our children are our most valuable resource," Rowe said. "Isn't it somewhat hypocritical, then, to attempt to achieve a balanced budget at the expense of reduced programs and services for the poorest of our infants, children and youth?"

While no single budget cut has been dramatic, Rowe said, the accumulated reductions in food stamps, Aid to Families with Dependent Children, day care, homemaker assistance and other programs have combined to put severe new stresses on many needy families.

"More families will break up . . . and more and more kids are going to be languishing in foster care," she said in an interview after her keynote speech to the National Adoption Exchange Conference at the Shoreham Hotel. "The adoption job is going to be that much more difficult, because more children will need placement, with fewer dollars available."

In Washington, Rowe said, Reagan administration cuts aimed primarily at removing working poor from welfare have the greatest impact on children, who make up more than half the case load.

The city government has eased the impact of the cuts by applying a $3 million "local band-aid" of payments to keep many families on the welfare rolls, Rowe said. "But we don't know how long we can keep that up," she added.

Regarding adoptions, she said, the D.C. government is seeking permanent placements for 2,185 children in foster care and may be forced to find new homes for many of the 5,000 children in troubled home situations that are supervised by child protective services.

Some 65 percent of foster children must wait more than two years for permanent placements, according to city officials. Rowe said the city currently spends $450,000 yearly to place about 200 children in adoptive homes, but current plans to expand that program are threatened by federal proposals to reduce spending via U.S. block grants for social services.

The federally supported three-day conference is aimed at the problems of the estimated 500,000 children nationwide in temporary foster homes. Of those, an estimated 100,000 never will return to their natural parents, according to federal estimates.

Clarence Hodges, commissioner of the federal Administration for Children, Youth and Families, while not directly discussing the impact of budget cuts, told the conference that the administration is committed to maintaining and even expanding "programs that work" such as Head Start, the preschool child-development program.

Hodges also pledged increased funding for minority-oriented adoption agencies, and "special initiatives" to help offset the impact of budget cuts on families. He did not provide specific figures.