NEW YORK, OCT. 17 -- Washington's real estate market has tumbled and talk of recession abounds, which is precisely what makes this the perfect time to open an office or factory in the nation's capital.

That, at least, was the sales pitch delivered today to more than 50 New York business executives at a luncheon seminar hosted by the Greater Washington Board of Trade. The presentation was the board's first high-profile bid to attract new companies to the region in four years and represented a major shift in its strategy after previously having cut back its recruitment of business to avoid worsening the region's congestion.

Trying to make the best a bad situation, panelists from the Washington business community stressed that office space is available at bargain prices because of overbuilding that has forced some developers to offer months of free rent and other perks to attract tenants.

The surplus presents "a real opportunity" for newcomers, said William C. Harris, the Board of Trade's president-elect. James L. Eichberg, president of the Smithy-Braedon Co. real estate firm, said competition among landlords has in some cases resulted in discounts of 10 percent to 40 percent on rents.

Panelists also wooed business by citing more familiar attributes such as Washington's well-trained labor force, quality of life, international links, universities and, above all, access to the federal government.

The approximately 55 guests who attended the seminar at Fifth Avenue's elegant Pierre Hotel included bankers, insurance and real estate executives and consultants who advise companies on where to locate new facilities.

No one expected a rapid influx of business to Washington based merely on the presentation. But members of the audience said such events were valuable in underlining that the area wanted to be considered as a potential site for new operations.

"It's a necessary thing to do because other communities are doing it," said Gene DePrez, a principal at PHH Fantus, a leading consulting firm here that advises companies on where to locate facilities.

"If you're not there {wooing business}, you tend to be forgotten, or information is not up to date, or there's a perception that nobody cares," DePrez said.

The last time the Board of Trade took such a show on the road to drum up new business for Washington was at a 1986 seminar in London. Two years ago, the group curtailed those efforts because of concern over crowded roads, high housing costs and a labor shortage.

Those worries have now been replaced by concern about the region's business slump, which has triggered the campaign that began today and will continue with similar seminars in Canada and on the U.S. West Coast.

"When things are going well, you don't really need to advertise. Now is the time to get aggressive," said William B. Wrench, Board of Trade president and a principal in the Wrench Group building concern.

Consultant DePrez praised the "candor" of the participants here, who openly acknowledged Washington's economic difficulties.

While admitting that Washington could not sustain the heady growth rates of the last decade, panelists said the region should do better than the rest of the country in the 1990s.

"While we are in an abrupt slowdown brought about by an overbuilt commercial real estate market, the fundamentals are still strong," said Harris, who heads Crestar Bank

In a particularly lively speech, Catholic University President Rev. William J. Byron noted that he and fellow educator William E. Kirwan, president of the University of Maryland at College Park, had been invited to be panelists because they represented the "only industry in America that has a positive balance of trade."

Byron cited "proximity to power" as Washington's strongest selling point, and said, "If you're not there, you ought to be, because otherwise you're going to be on the outside looking in, instead of inside making things happen."