Contending that Washington's rental housing shortage is exaggerated, the city's two largest real estate organizations yesterday rejected proposals for a moratorium on most evictions.

But the groups, the Washington Board of Realtors and the Apartment and Office Building Association (AOPA), announced that they would establish and finance a registry to find new quarters for families displaced by private real estate operations.

The decision was announced at a District Building news conference. It came at a time of growing protest against housing displacements being voiced by tenant groups, backed in an election year by many city politicians.

Tenants are objecting to the withdrawal of properties from the rental market for sale or redevelopment, or for conversion into offices and condominiums. Real estate interests contend that rent control is forcing such actions.

The eviction moratorium proposal that was turned down by the two groups yesterday was made on March 18 by D.C. City Council Chairman Sterling Tucker, currently one of seven likely contenders for the mayor's office.

Tucker read the small print in the realtors' response to his proposal, and told the reporters that he did not regard it as a full rejection.

The realtors declared: " . . . the (two) associations will exercise all available means to persuade developers to delay evictions until each family scheduled to be displaced has been offered comparable housing."

Raymond J. Howar, first vice president of the realtor group, said "we believe that the number of available (rental) dwelling units is sufficient to meet the present demand."

Creation of the new registry, which will have an initial annual budget of $50,000, "will go far in reducing the fear and uncertainty felt by most persons or families facing displacement."

Howar said the D.C. government should step up its own efforts to find housing for those displaced.

AOPA president Irving M. Kriegsfeld cited two sets of figures that, he said, indicate that the city's housing market is not as tight as is widely believed.

The Metropolitan Washington Council of Governments completed a survey of Washington rental housing last November which, Kriegsfeld said, shows an overall apartment vacancy rate in the city of 4.03 percent. For low-rent housing, he said the vacancy rate was an even higher 4.73 percent.

Each month, more than 3,500 apartment units become available for rent, he noted.

Kriegsfeld also reported that, as of February, the total conversion of apartments in the District into condominiums totaled only 13 buildings with 985 dwelling units. (City permits have been issued that would allow the conversion of more than 2,000 units, AOPA reported.)

With the conversions, he said 32 percent of the former tenants bought their units. Of all former tenants, only 3 percent said they could not afford to buy.

The real estate groups used the news conference to mount a new assault on the city's recent three-year renewal of the rent control law.

"As we have repeated time and time again," Howar said, "rent control is the major force which has brought a pervasive sense of uncertainty to the rental housing market. At the very least, the city can take steps now to decontrol vacant . . . and . . . luxury apartments."

Tucker voiced hope that the city ultimately can eliminate rent control by expanding its housing supply.

But the problem of a shrinking supply of housing "has such an explosive potential right now" that decontrol is impossible, Tucker said.