The Barry administration, citing the slump in the region's economy, has mounted a strong last-minute effort to derail new downtown zoning requirements that have angered city developers.

City Administrator Carol B. Thompson asked the D.C. Zoning Commission in a letter this week to reconsider its recent decision to require developers to build housing -- not only the more lucrative office buildings -- on the east side of downtown.

It is unusual, and maybe unprecedented, for the mayor's office to try to turn around the Zoning Commission after it has reached a tentative decision on an issue, real estate experts said.

Even more unusual, they said, is a separate letter to the commission from Raymond A. Skinner, executive director of the city's Office of Business and Economic Development.

In the letter, Skinner essentially rescinded testimony he gave the commission last spring in which he supported requiring more extensive downtown housing than desired by developers.

The commission voted in favor of that position on Sept. 17.

The administration's campaign against the Zoning Commission's plan angered some community activists and delighted developer representatives, who have been struggling for years over the best means to build housing downtown. Some proponents of low-income housing also like the administration's campaign, for their own reasons.

"This is nothing but an end-run catering to developers," said Terry Lynch, executive director of the Downtown Cluster of Congregations, a supporter of the Zoning Commission plan. "What the Barry administration has done is put zoning and planning up for sale."

But zoning lawyer Whayne S. Quin said the letters "are very important, because they seem to confirm what the business community has been saying."

Quin said many of the provisions of the commission's tentative downtown housing plan are unworkable because they rely too much on mandates, as opposed to financial incentives, to encourage developers to build housing. "I just don't think you can provide housing by the stick method," he said.

The administration's action on downtown housing is among several important issues being watched closely by politicians and community activists as Barry's tenure as mayor draws to a close. Some D.C. Council members have expressed concern that Barry would use his final months in office to help friends and political supporters, such as developers.

Last month, for example, Barry asked the D.C. Council to approve sale of some Northeast Washington apartments to a group including past supporter Conrad Monts and close Barry friend Daniel Butler. The group is seeking a $1 million loan from the city.

Yesterday, Council Chairman David A. Clarke (D) said he would propose emergency legislation requiring Barry to submit for council review any contract or lease worth more than $1 million.

"Commitments binding the city for large amounts . . . need the involvement of those who will have to be a part of paying the bills," Clarke said.

Developers are concerned about the downtown plan because the area in question -- including Chinatown and the area around Mount Vernon Square -- includes many potentially lucrative parcels, even though most of it is rundown. It includes two sites where developer Oliver Carr plans large projects.

Developers say that given the economy's weak condition, the commission's action will end virtually all development in that area because it would reduce projects' profitability beyond the point where they would be viable.

The controversy centers on two objectives favored by almost everybody. First is the concept of a "living downtown," one combining offices with houses and arts uses. Activists such as Lynch say a drab downtown saps economic vitality.

The second is the desire for low- and middle-income housing. All sides have known that the city eventually would levy a special tax on downtown office developers, requiring them to pay into a trust fund dedicated to housing. The question has been whether the housing would be built downtown or in neighborhoods around the city. Downtown land is extraordinarily expensive. Developers point out that it would be expensive to build residences downtown, and that the residences would be affordable only to the well-to-do.

Many activists for low-income housing joined developers in opposing the commission's plan because a housing trust fund could build many more housing units in outlying neighborhoods than it could downtown.

Proponents of the plan the commission tentatively adopted by a 3 to 2 vote say it would add about 6,000 homes downtown. The panel is scheduled to decide the case next month.

In her letter, Thompson said the commission's plan is too ambitious in its housing goals for downtown and does not take into account the real-estate slump.

In a statement released by her office yesterday, Thompson said her position represents a compromise between competing interests. Her spokesman said Barry agrees.