D.C. Mayor Walter E. Washington proposed to the D.C. City Council yesterday legislation that would make it more difficult for apartment building owners to convert their properties to condominiums or other uses.

The proposed legislation would make any apartment complex ineligible for conversion to condominium if an efficiency apartment there rents for less than $262.50, a one-bedroom rents for less than $300, a two-bedroom rents for under $375, and any larger apartment rents for less than $422, according to a press release.

Under the emergency condominium act now in effect, rental units can be converted if an efficiency there rents for under $205, ranging up to rentals of under $403 for any apartment of three or more bedrooms.

A spokesman for the city government said the legislation was proposed because of figures showing an "incredible" increase in conversions and applications for conversions so far this year.

More than 1,000 rental units have been converted to condominiums this year, compared to 430 for all of last year, according to the press release. An additional 1,600 tenants "are living in an unsettled state because landlords have received permission to convert but have not yet done so," the release stated.

In addition, as of April 25, of this year apartment building owners had applied for certificates of eligibility to convert 1,949 rental units to condominiums, compared to 1,995 submitted applications during all of this year, the city rent administrator received notices of more than 1,400 units being removed from the rental market. Compared to an average three-month period during the last nine months of last year, that figure represents an 861 percent increase, the press release said.

The mayor's proposal, which was drafted by the city's housing department with the assistance of the D.C. Rental Accommodations Office, also would require landlords who have qualified for condominium conversion to inform prospective tenants that the building might be converted before entering into rental agreements.

In addition, landlords would have to reapply after six months if they have not converted a building that has been certified as elegible, a move designed to make certain that tenants will not have the continuing uncertainty of possible conversion," the release said.

Also, apartment building owners would not be able to convert their properties to apartment hotels or other transient uses unless their buildings are specifically licensed for such a purpose.

John T. O'Neill, of the Apartment and Office Building Association, said yesterday that he was not familiar with the proposed legislation, but suspected that it was linked to the mayor's "sagging campaign."

"Housing has become the whipping boy for this political campaign." he said. "It's a funny kind of situation to deal with the inadequacies of the rent control law by forcing people to stay in the rental business without giving them rental increases."

O'Neill and others in the apartment building industry contend that the city's rent control laws force some building owners to convert their properties because they can't afford to maintain their buildings without more substantial rent increases.