Despite the objections of several local governing bodies, the Montgomery County Planning Board last week approved a site plan for a major development in Somerset that will include three high-rise apartment complexes and 85 town houses.

The development, planned for the 18-acre Bergdoll tract just north of Friendship Heights and west of Wisconsin Avenue, will include 766 dwelling units and take five to 10 years to complete, according to plans submitted by the project developer, Community Somerset Associates.

"As far as we're concerned, this is the final approval for what should be built on the site," said Planning Board spokesman John Hoover. "Now it's up to the developer."

But at least one local group said it was ready to go to court to block the project. Alfred Muller, chairman of the Village of Friendship Heights Council, said the council is prepared to go to court to fight one aspect of the proposal - the extension of Friendship Boulevard. The developers plan to extend the boulevard to Wisconsin Avenue, a move called for in the Friendship Heights Sector Plan for future development in the area. Council members oppose that move because they say it will increase traffic in Friendship Heights Village, which maintains its own roads.

"They maintain their own streets," said Hoover. "Now they want to know if they can prevent further road construction. Nobody knows the answer to that yet. It's undoubtedly a matter for litigation."

Officials from Somerset are also considering a court action, according to town attorney Paul McGuckian. Somerset officials claim the developers are breaking an agreement they made with the municipality in 1968 to construct only 600 dwelling units on the tract.

Under county zoning laws, the developers are required to make 15 percent of the units "moderatley priced" in the range of $35,000 to $45,000. As compensation for the low-cost housing construction, the developer is allowed to build 20 percent more units on his land.

Community Somerset Associates has chosen to build the additional units, making the total more than the 600-unit maximum called for in the 1968 Somerset agreement. "We haven't decided yet whether we'll take this to court," McGuckian said. "But we feel very strongly that the developers should not have gone above 600 units without our consent."

Other local groups expressing reservations about the project at last week's meeting were the Coordinating Committee of Friendship Heights, the Elizabeth Condominium Association and the Village of Chevy Chase. "There's always been opposition to developing this tract," Hoover said. "It's been going on for the past 10 years."

The developers plan to complete the project in three phases, building one high rise apartment and several town houses at a time. Also slated for completion in the first phase is the extension of Frienship Boulevard.