The D.C. government, concerned that skilled blue collar jobs are being drawn from the city to the suburbs, is holding up construction of a $15 million central maintenance plant that Metro is ready to build in Alexandria.

Metro officials want to transfer about 450 people now employed at a Metro shop at 14th and U streets NW, and the Brentwood railyard near Union Station to the future Alexandria plant and three "satellite" maintenance facilities in the suburbs.

General Manager Richard Page says the new facilities are badly needed for maintenance of both the bus and rail system.

Four times since April 22, the Metro staff has sought final clearance from the board to seek a contractor to build the facility. Each time, District of Columbia members have asked for a deferral, even though the city in past votes has approved the project and its proposed site just inside the Capital Beltway.

The Rev. Jerry Moore, representing the District of Columbia, said the city is not threatening a veto but merely wants answers to questions about Metro's long-term employment policy."

"If you deport your skilled jobs", Moore said, " . . . it lessens the opportunities of residents of the District of Columbia."

The city's tactics have not been well received by officials of other governments who are anxious to start construction. The dispute offers a study of how contrasting political objectives of the eight local governments in Metro can slow development of the mass transit system.

Metro has planned the center since 1974. The goal is to place equipment and employes needed for maintenance of nonmoving property -- track, stations, electrical wiring, bus garages and buildings, for instance -- in one central facility and at satellite shops on the Metrorail system's outer segments.

In addition to its concern over loss of jobs, the city has said that centralizing maintenance might waste money by adding to travel time. In a letter to Moore last week, Page rejected this reasoning and a suggestion from Moore that some jobs intended for the suburbs might go instead to a site on the New York Avenue corridor.

A prime attraction of the Alexandria site is that Metro already owns the land, Page said. "It worries me that Metrorail is six years old and we still don't have a facility of this type . . . This should have been a precondition to rail operations," he said.

Metro officials maintain that the District of Columbia already is doing well in terms of transit employment, with about 80 percent of the agency's 7,000 jobs based in the city. Moore counters that it remains unclear how many of those people live in the D.C.

In an earlier letter to Moore, Page noted that Metro is going to be seeking a site for a large, central warehouse for spare parts, tires and other commodities purchased by Metro. "Your assistance on the location of this facility . . . will be invaluable," his letter said. Moore said the city would follow up Page's request but expressed concern that warehouse jobs might be unskilled.

About 235 of the employes who would move to the suburbs now work out of the 14th and U facility, located in a neighborhood that the city has targeted for revitalization. The shop there is scheduled to close in any event, because the building is to be demolished to make way for a future Green/Yellow Line subway station below it.

Construction is supposed to begin some time after 1985, but federal grant shortages make schedules extremely tentative.