Widespread discontent is spilling out of the Massey Building, the 12-story tower where Fairfax County's usually tightly buttoned bureaucracy toils.

Fairfax, not so long ago a tranquil suburban bedroom community, is expected to be the most populous jurisdiction in the Washington area by the end of the decade -- a major urban center in its own right. But according to a number of highranking members of the county bureaucracy, Fairfax is ill-prepared to shoulder the burdens of its future growth.

In an extraordinary airing of their discontent, seven top appointed officials recently called the county government leaderless and demoralized. Three former officials who recently resigned expressed similar views.

The 10 present and former officials agreed to discuss their views provided they were not identified. But even with that proviso, the extend of their grievances was unusual in a county government that generally keeps its dirty laundry out of sight.

Targets of the criticism were the nine members of the Fairfax Board of Supervisors and, to a lesser extent, Acting County Executive J. Hamilton Lambert, who was appointed by the board. Lambert has been filling in for 17 months while his bosses search for a new executive.

The officials interviewed said their concerns went beyond the grumblings that take place in the corridors of any bureaucracy.

"I'm not talking about office gripes," said one top official, "but questions like where is this county going? But no one wants to ask that. It's as if we were all fat, rich, dumb and happy."

The county's wealth, said another official, masks serious problems that will arise in the 1980s.

"Located near Washington, Fairfax hasn't really had to prove itself," the official said. "The federal government has been a stimulus with jobs. That's why things keep going, not because county leaders are addressing policy issues."

But, he said, "as the energy situation and inflation get worse, as growth overtakes services, as the regional competition for jobs increases, what will happen? There will be a slow deterioration that will ultimately affect the quality of life that attracted people here. That is already happening."

Among the questions that critics claim have been deferred or evaded are these:

What should the county do about a master plan that encourages the building of single-family homes at a time when the energy crisis and inflation are making these houses an increasingly unattractive economic proposition? One possible alternative: higher-density zoning on scattered vacant sites closer to the city -- especially around future subway stations. But any such proposal would arouse intense opposition from residents who view apartment buildings as intrusions on the suburban landscape.

Should the county zone land for a new industrial corridor to remain competitive with other areas? The county is short of prime industrial sites but, her again, efforts to rezone residential land for industry would arouse fierce opposition from local residents.

Should the county pay for badly needed highway projects such as the Springfield bypass and others which the state highway department says it can't afford? Lambert's new budget, now pending before the supervisors, does not address the highway question.

How are buses and cars going to get to two future subway stations -- Huntington Avenue and Franconia -- unless the county undertakes major road improvements near the stations?

Running through most of the criticism of the Fairfax supervisors and Lambert was a single theme: There is no leadership, motovation or direction from the top.

One official recalled the atmosphere at a recent management workshop for county managers. "It was vitriolic, really vitriolic," he said.

Some officials were said to have complained that they spend too much time as "handmaidens" to the supervisors. Several cited the supervisors' request for a survey to find out if showers should be provided for county employes who jog to work. Result of the survey: County employes said showers would be a waste of money, but how about providing a bike rack?

The board, which generally meets every Monday, doesn't know how to apportion its time, say critics. One example: Northern Virginia's legislators and state Highway Commissioner Harold C. King were invited by the board to come to the Massey Building to discuss solutions to highway problems in the traffic-congested county. The group waited for an hour while the supervisors slogged through minor items on their agenda.

Time spent in trivia is a frequent criticism. Recently, for example, the supervisors held a public hearing on a proposed special exception "to permit construction of a canopy over pump islands, kiosk and an enlarged pump island at an existing service stateion at 8050 Lee Hwy. on 35,983 square feet . . ."

After deliberating for about 40 minutes, the supervisors did what their staff recommended. They approved the canopy, kiosk and enlarged pump island.

While department heads were critical of the supervisors, some also placed blame on the acting county executive's office.

Lambert has been urged repeatedly by the supervisors to take the job permanently. But the 39-year-old veteran administrator has declined for "personal reasons." His decision surprised some people who work for him, and some of the morale problems are traced to disappointment that Lambert would not take the post.

A high school graduate who started his career with the county in 1959 as an assistant map draftsman, Lambert is viewed by people who have worked with him as smart, dedicated and hardworking, but more interested in the care and feeding of the often-demanding supervisors than in taking on major but potentially divisive issues.

"Jay grew up there (in the county government)," said one former county official. "He's an incredibly bright guy, but he doesn't use his mind. He picks targets of opportunity and winners. He won't touch the hard ones."

However, some of Lambert's critics acknowledge that the job of county executive in Fairfax has built-in problems. The position is appointive -- in suburban Maryland it is elective -- and that means that the supervisors ultimately hold all the cards.

But the supervisors don't always seem sure how they want to play their cards. Chairman John F. Herrity, a Republican, has tried to seize the leadership reins, but he has few specific powers beyond those of his eight colleagues. And they do not seem to be disposed to defer to Herrity.

For his part, Lambert takes a dim view of the criticism and says he plans to bring forward a number of policy questions that his critics say he has stifled or kept on a back burner. They include, he said, a report on whether the county should create its own bus system free of Metro, proposals that would require developers to buffer noise that would affect homes built near highways and other noisy places and a review of the master plan, which some critics say is outdated.

Board Vice Chairman Martha V. Pennino (D-Centreville), who often seizes a leadership role on the board when Herrity finds himself isolated, reacted angrily to the criticism leveled against the board and Lambert, whom she hoped would be the permanent county executive.

"If they (the staff) think they're there to run the government, they're sadly mistaken . . . What the staff is telling me is that they don't want citizen government. They want to have it their way."

But Supervisor Marie B. Travesky (R-Springfield) acknowledged, "There are some problems." Echoing the critics, she said: "This board has got to set goals. It is not doing that now. You can't bring up anything during meetings that sounds like a philosophical argument without somebody jumping down your throat for wasting money or time . . . I feel so frustrated . . . Something has to be done."