An eight-story District government office building - to be built over the Judiciary Square Metro stop at 4th and D streets NW - is now in the first planning stages, according to city officials.

A group of 20 architectural firms bidding on the project has been narrowed to 10, said director of the city Office of Program Management. A firm will be selected after officials from the 10 firms have been interviewed, he said.

The city hopes the new office building, which has a construction budget limit of $26.5 million, will reduce the multimillion dollar cost of leasing government office space, according to Jones. He said the city now leases 3.4 million square feet of space at a cost of more than $10 million each year.

"This new building will not reduce all the costs of leasing office space, but it should reduce at least half of the problem," said Jones, who added that funds for a second municipal office building were cut from the budget by Congress.

Plans call for the new building to have eight floors above ground and two floors for underground parking, with a maximum of 550,000 square feet, said Jones.

"There is no way we can tell at this point how many people this will represent," added Jones, who said the new facility will house a number of District agen- cies, that have "different space requirement."

[WORD ILLEGIBLE] , chief of space utilization [WORD ILLEGIBlE] District government, said, "The new office building will enable D.C. to give up leased space . . . but what space it will give up is not yet decided."

As an example, Gee said the City Council, which indicated an interest in the structure, has not yet decided if it wants to move. Substantial improvements have been made recently to the council's present office space in the District Building.

Gee said final decisions on [WORD ILLEGIBLE] offices will move into the new building will not be made until at least Oct. 1. He added, however, that there is a strong possibility that agencies in the Presidential Building at 415 12th St. NW, which include the Department of Transportation, Environmental Services and Board of Education, will be moved to the new structure.

In their application to the federal government, District officials said the new office building would permit the city to terminate leases on "two major buildings, the Potomac Building (at 613 G St. NW) and the Presidential Building," which now cost the District approximately $3 million a year to lease.

Plans to make the area around 4th and D streets NW into a municipal center have been mulled over since Maj. Charles Pierre L 'Enfant originally designed the city in 1791. The new project, which was funded by Congress in the 1978 budget, will further improve the once decaying area where the new District Court and U.S. Tax Court buildings have been constructed.

The new building will pose a set of interesting problems for the architectural firm that is finally chosen, according to city officials. D.C. officlas are suggesting that the architects design the office space with movable or demountable partitions, because no one yet knows who will be moved into what space or how much space they will need.

Floyd Holliday, project manager for the new office building, said the architect will also be expected to show the city how it can use an energy efficient system to operate the building. He said the city is interested in a solar energy system or other modifications to rduce both heating and cooling costs.