Faced with the prospect of "the bottom falling out of the housing market and widespread unemployment in construction trades," the National Association of Home Builders again is urging Congress and the White House to support a "low-cost" mortgage assistance program to stimulate the sale of moderately priced new homes."

A small group of leading homebuilders met with NAHB staff members here earlier this week to discuss legislation that would provide a federal subsidy for some below-market mortgage loans. Reactivation of the so-called Brooke-Cranston tandem program "would stablize housing production," Fort Worth, Tex., builder and NAHB Vice President Herman J. Smith recently told the House subcommittee on housing and community development.

The program, which was used to earlier to stimulate housing production, enables the federal government to make commitments with private lending institutions to purchase mortgages at a predetermined interest rate. The government then can resell the mortgages on the secondary market, thus recapturing most of the initial outlay.

Meanwhile, there are indications that Congress might look favorably on a limited subsidy for limited number of mortgages at 2 percent below the market rate, which now is between 15 percent and 17 percent in some parts of the nation.Even with an initial budget outlay of $10 billion for mortgages, the actual cost to the government is estimated at $900 million, which is considered a minimal budgetary impact.