New York has Gracie Mansion, Los Angeles has Getty House and now there is new momentum to establish a similar mayoral mansion here at a cost of up to $500,000.

Mayor Marion Barry, who scoffed at such a notion only six months ago, yesterday described as "an admirable gesture" a bill introduced by D.C. City Council member Jerry A. Moore Jr. (R-At Large) to spend the money for an official residence for the mayor.

"If Jerry Moore wants to do it, that's probably an idea whose time has finally come," Barry said. "I think he wants to add some stature to the office of mayor."

Moore's bill would authorize the D.C. Department of General Services to purchase a building for use as the official residence for the mayor or to renovate a city-owned property for that purpose, subject to council approval.

The project would be financed from general revenues or as part of the city's long-term capital improvements program. No specific buildings are mentioned in the proposed legislation.

The building would be comparable in function to Gracie Mansion, the living quarters for New York's mayor, and Getty House, the official residence of the mayor of Los Angeles.

"The idea for an official residence has been batted around almost since the beginning of home rule," Moore said yesterday. "It's not unusual for cities to have official residences for the mayor. . . . I just think it's time for the city to move forward with it."

Moore said he could see nothing wrong with authorizing a costly new mayoral perquisite during a time that city officials and residents are faced with major cuts in federal aid for jobs, housing and welfare.

"The times do not relieve one of their responsibilities," he said. "If you have a gas bill to pay and you don't, it's no excuse to say that the times are bad. . . . It's not related to the times. It's related to your responsibility."

Last July, City Council Chairman Arrington Dixon said that he was exploring the possibility of establishing a showplace residence for the mayor on Pennsylvania Avenue that could be used to wine and dine visiting dignitaries. Dixon had in mind renovating a former schoolhouse at 921 Pennsylvania Ave. SE on Capitol Hill.

When asked then for his opinion of Dixon's proposal, the mayor snapped: "I already have a house . . . . That's the last thing on my mind."

But yesterday, Barry praised Moore as "a great council member" who had drafted a proposal worthy of the council's deliberations. He added, however, that he would reserve judgment until after the council has acted.

Dixon, a potential candidate for mayor, said yesterday that Moore's measure "merits attention" and that he supports "the initiative to look at this."

In citing precedents for such a project, Dixon noted yesterday that the board of the University of the District of Columbia voted last month to purchase a newly built $330,000 house in the Chevy Chase section of the city as the official residence of its president.

Dixon also argued that establishment of a mayoral mansion actually might save money in the long run, by eliminating the need to spend many thousands of dollars on residential security systems every time a new mayor takes office.

There have been two mayors since the city was granted limited home rule in 1975--Barry and Walter E. Washington. The security for Washington's home consisted of a police cruiser parked out front around-the-clock. A guard house, infrared detectors and other security equipment worth a total of more than $13,000 have been installed at Barry's house.

Three other mayoral aspirants, council members John A. Wilson (D-Ward 2), Betty Ann Kane (D-At-Large), and John L. Ray (D-At-Large), said yesterday that they were opposed to Moore's bill.

"There's no need at all to do that . . . . We've got enough perks already," said Wilson, chairman of the Finance and Revenue Committee. "It would be a wonderful gesture for someone in the community to donate it. But the city can't afford it at this point."

Kane said that while she had previously favored converting a building for use by the mayor in greeting visiting dignataries and conducting ceremonies, she was opposed to establishing an official residence that would further isolate the mayor from the public. "I don't think mayors need to be treated like kings," Kane said.

Ray said, through an aide, that the money could be better spent on the D.C. school system. Establishing an official residence "is not the city's most pressing problem," the aide said.

Barry and his wife, Effi, live in a four-bedroom brick house at 3607 Suitland Rd. SE, a predominantly black, middle-class neighborhood in the Hillcrest area. Barry, who as mayor receives a salary of $64,200 a year and $20,000 annually in discretionary funds, purchased the property in 1979 for $125,000.

The mayor said yesterday that while his home is adequate for official entertaining, "My house has taken a lot of wear and tear."

"We had to have the rug cleaned twice," Barry said. "It's tough on our house, but we understand that's part of the job."