Congressional advocates of housing programs big-city mayors and housing industry spokesmen warned President Carter yesterday that they would fight the reported proposal to transfer most federal funds for subsidized housing programs to finance Carter's welfare reform plan.

Sens. John Sparkman (D-Ala.) and William Proxmire (D-Wis.), senior members of the Senate Housing subcommittee, teed off on the suggestion, embodied in a memorandum from the Office of Management and Budget, that $4.9 billion could be shifted from housing assistance to help pay for improved welfare benefits.

Sparkman wrote Carter yesterday that the OMB memo "sounds like the discredited policy advanced by former President Nixon . . . It would be tragic to direct federal policy on that path again."

Proxmire, also stressing the Nixonian antecedents of the proposal, said "If they're really planning this, it's outageous. Congress wants more housing started, not less."

The OMB memo had suggested that federally subsidized housing starts could be reduced from 400,000 units a year to 50,000.

Mayor Lee Alexander of Syracuse, president of the U.S. Conference of Mayors, called the proposal "nothing more than a scheme to rob Peter to pay Paul."

Jack Shriver of Norfolk, president of the National Association of Housing and Redevelopment Officials, said, "What OMB is proposing is to increase the number of families competing for low-cost housing while tightening the housing supply by reducing government assistance into the hands production, In effect, this would put of slum landlords . . . and encourage them to keep the slums as they are."

Robert Arquilla, president of the National Association of Home Builders, called the OMB suggestion "a tragic social and economic mistake," adding that "it would undermine programs under way in thousands of cities and towns to revitalize deteriorated neighborhoods and slow activity not only in the housing industry but the entire economy."