The D.C. Zoning Commission postponed action yesterday on massive changes in the city's hotel regulations, but indicated it is leaning toward approving measures that would severely restrict the expansion of existing hotels in residential areas.

If the measures are approved, it appears that the controversial proposed expansion of the Washington Hilton Hotel onto property now occupied by three Columbia Road apartment buildings would be blocked.

The proposal for the Hilton's expansion had outraged many Adams-Morgan residents.

"If they go the way they seem to be going, it looks like they're on our side," said Nell MacCracken, one of the more than 250 tenants who live in the three threatened buildings. "It shows that justice can be served, that they [the zoning board] are an independent body from the mayor."

Last month the mayor's planning office made recommendations that would have permitted some hotels, including the Hilton to expand -- reversing a position the mayor took last summer at a community rally.

The zoning commissioners indicated yesterday they would like to see hotels in residential areas expand only onto vacant property that the hotel operator already owns, as of a set date. Last Jan. 1 was one possibility. Expanison would require case-by-case approval from the Board of Zoning Adjustment, or on an individual rezoning request to the Zoning Commission.

Under such a definition the Fairfax hotel on Massachusetts Avenue apparently could expand, for example.

Some zoning commissioners also said they support banning new hotel development in residential areas, as recommended by the city Planning Department. Currently, there is an emergency moratorium on hotel development in the city.

The board asked city planners to return on March 20 with more information on the definition of hotels, new hotel development and the conversion of apartment buildings to hotels.

New hotel development and hotel conversion will have significant impact on the character of many neighborhoods near downtown, community activists stressed.

Leonard Hickman, executive vice president of the Hotel Association of Washington, yesterday's said meeting showed that commissioners "neet to do a lot more discussing and thinking about the subject."

Some of the proposals pleased him, others did not, and some will be open to legal challenge, Hickman said. "We're still optimistic," he added.

The zoning regulations under consideration would result in the most massive changes in hotel regulations in the city in more than 20 years.

The city currently has about 16,000 hotel rooms, a slight decrease since 1970. Meanwhile, the number of hotel rooms in Washington's suburbs has tripled in the last 15 years.

The hotel association argues that as Washington has become an international and cultural center, with the convention center schedule to be built over the next few years, the city should encourage hotel development, not restrict it.