About 70 U.S. corporations or trade associations are actively considering relocating their headquarters or substantial portions of their operations to the Washington metropolitan area, a business spokesman said yesterday.

Addressing a luncheon of the Metropolitan Board of Trade, lawyer and board president R. Robert Linowes revealed that the 70 top "prospects" are among about 170 organizations that have inquired about moving here so far in 1978, in response to the local community's business development campaign. "The Case for Washington."

The regional campaign, complete with advertising and mail promotions designed to attract corporate offices and trade association here, started in 1976.

To date, Linowes said yesterday. 26 such firms or associations have made commitments to move here. The 26 organizations were in contact with the Board of Trade program, but John Tydings, executive vice president of the board, emphasized in an interview yesterday that the board was not the only local impetus for the new arrivals.

Tydings said he could not provide names of the 70 current top "prospects" but he said there are four major categories - office space users, retail companies, research and development firms and distribution or wholesale enterprises.

Moreover, Tydings revealed that a significant shift is taking place in the types of organizations interested in a Washington location. While most inquires in the past came from the non-profit sector (trade groups, unions), the "clearly predominant" sector now is for-profit business, Tydings said.

More than 70 percent of groups now interested in Washington are such "for-profit" corporations, Tydings stated.

The most publicized plan to move to Washington has been Mobil Oil Corp's. The petroleum giant will move more than 1,000 workers out of New York City to Fairfax County by mid-1980. A domestic headquarters is being constructed there now.

In the last 18 months, organizations that have announced a move to Washington include such major trade groups as the Edison Electric Institute (from New York City, in 1979) Associated Retail Bakers of America (Chicago to Hyattsville), Cigar Association of America (New York to D.C.) and the Industrial Gas Cleaning Institute (Norwalk, Conn., to Alexandria, as of June 15).

Corporations that have opened or announced new area offices include Aamco Transmission. Howmet Co., Ryan Computer Systems. Peabody Coal and Wheelabrator-Frye.

Linowes also detailed yesterday his belief that area businesses must become "politically active" to have an impact on regional government decisions.

As reported earlier, the Board of Trade has established local political action committees in Maryland. Virginia and D.C. to channel legal business political donations to candidates "who best advance sound economic and governmental policies."*