The Arlington County Board approved plans early yesterday for the revitalization of the Clarendon neighborhood, after rejecting components of a rival plan that called for more intensive development around the community's Metro station.

The plans, similiar to proposals by a citizens' group and the county staff, will allow roughly 2.5 million square feet of new offices, hotels, and stores in the neighborhood, once called Northern Virginia's downtown.

The new land-use plans would more than double the existing million square feet of commercial space in the area. Under a new zoning classification, 6- to 10-story offices will be permitted near the recently approved 14-story Olmsted Foundation Building, which is expected to be the centerpiece of new construction near the Metro stop.

"It was a good step toward redevelopment in Clarendon, and at the same time toward preservation of the surrounding single-family neighborhood," said William Gearhart, president of the Lyon Village Citizens Association, which joined with four other neighborhood groups in backing the proposals of the Ballston-Virginia Square Citizens' Coalition.

Until the late 1950s, the Clarendon area was a hub of business and social activity in the county. In recent years many of the older businesses left, to be replaced by what some call "Little Saigon," a collection of small businesses run by former Asian refugees. The small size of many Clarendon land parcels is one reason county staffers predict most the proposed redevelopment will not occur until the 1990s.

Advocates of a rival plan backed by the county planning commission warned that the coalition plan is too restrictive and provides insufficient incentives for developers. "I see no reason for a 2.5 million square feet cap on the Metro line," said John F. Schiller, president of the Clarendon Business Association. "A six million cap would be more realistic."

The approved plan does not specifically mention the 2.5 million figure, but that is the amount of commercial space the county staff estimated the new plan will allow.

The board voted unaminously for the final plan, after board member Walter L. Frankland failed to gain support for allowing more development near the Metro stop. "I think it's so important that Clarendon not just be a string of offices," board member Ellen C. Bozman said later.

"I think the board would like to preserve the Main Street U.S.A. character of Clarendon, and that in 20 years it would have more of the character of M Street in downtown Washington than of Crystal City," said Robert M. Glidden, who was active in the citizens' coalition. Glidden expressed concern in an interview, however, that the new plan may lead to pressure for additional commercial development in the surrounding residential neighborhoods.

The county board directed its staff to draw up requirements for building heights to decrease farther away from the Olmsted Building in areas bordered by Wilson and Washington boulevards. Two other areas on North 10th Street and North Fillmore Street may be rezoned later to a second new classification permitting stores, townhouses and small professional offices, board members said.

In other action, the board appointed Charles G. Flinn as county attorney. Flinn had been acting as county attorney since last summer when Jerry K. Emrich resigned. Flinn will be directly responsible to the county board instead of the county manager under new state legislation which took effect this month.