A 60-car parking lot for government workers has been carved out of the national park on the Ellipse behind the White House for employes whose cars were displaced by construction of a pedestrian mall between the White House and the Treasury building.

The gravel lot, directly across from the main entrance of the Commerce Department on 15th Street NW, is sandwiched between the Ellipse's tennis courts and the Boy Scout Memorial. It replaces pits for playing horseshoes and a row of park benches.

The new parking spaces there, like the rest of the Ellipse and several adjoining public streets, are reserved for government workers who park free.

Sandra Alley, spokeswoman for the National Park Service, said the new lot is reserved for White House and Treasury workers who used to park along East Executive Drive, now closed for construction.

Three years ago, East Executive was closed to through traffic and converted to parking for police and White House staffers. Earlier this month the block-long street was fenced off for construction of a $3.8 million pedestrian mall.

Alley said the new lot, which opened last week, is considered temporary and is scheduled to be removed by the end of October. She said there were no estimates available as to the cost of making and then unmaking the temporary lot.

Charles Atherton, secretary of the Commission on Fine Arts, which is the federal arbitrator of architectural esthetics in much of Washington, called the location of the parking lot "unfortunate."

"Generally the Park Service checks with us before they do anything with the important parks around the White House," he said. "That is no place for a parking lot. Even if they call it temporary, the word temporary sends shivers up and down my spine."

Atherton recalled that "temporary" war buildings constructed in Washington in 1918 were not torn down until the 1970s.

This week the new lot on the Ellipse was filled. Dave Manly, a planner in the Commerce Department's environmental office, picked his way through the rows of cars occupying the muddy lot, which he does not get to use.

"This is a bad parking lot and a bad idea for a lot," he said. "In the summertime, there is a league from the Commerce Department that plays horseshoes every day. And I like to play tennis on the court over there. But who wants to play with a bunch of cars parked next to the fence?"

Manly said that 10 to 12 park benches were lost to the parking lot -- "the only benches where we could sit to take a break."

"Nobody canvassed us to ask what we thought about losing our space in the park," Manly said. "This nice recreational area cost the government nothing and meant a lot to people who work near here."

The 54-acre Ellipse was part of Pierre L'Enfant's 1791 plan for the city.

This is not the first time that government agencies have eyed the national park for other than park use. Over the years, office buildings have been contemplated for the Ellipse, but none has ever been built.