The Fairfax County Board of Supervisors, moving on a proposal that has been stalled by political debate for a decade, voted 6 to 1 yesterday to ask the staff to draw up a request for bids on a new government complex west of Fairfax City.

The county board has repeatedly declined to seek voter approval to borrow an estimated $70 million to build the government center, which some politicians have called a "monument to bureaucracy."

Now, some of those politicians are hailing a joint venture to build the center as an innovative solution. Under the plan, the county would give a portion of the 183 acres of prime real estate it owns south of the intersection of I-66 and Rte. 50 to a developer in exchange for the construction of a government center. There would be no referendum on borrowing funds.

"We need a functional building," said board Chairman John F. Herrity, who in the past has blasted the government complex and its supporters but now is championing the joint venture idea.

The vote "absolutely was a turning point," said board Vice Chairman Martha V. Pennino, a Democrat who has long endorsed a new government center, adding that the need has "become so acute that it's even obvious to Mr. Herrity."

Supervisor Audrey Moore, a Democrat and for years a vocal opponent of the new center, voted against the proposal. Supervisors Nancy Falck and T. Farrell Egge, both Republicans, were not present for the vote, though Egge said later he supported a joint venture development.

In other action at yesterday's meeting, the last before its summer recess, the county board took a preliminary step toward commissioning a study of the state's troubled Camp 30 prison; told county staff members to continue studying plans for a one-year experiment in commuter rail service between Fredericksburg, Va., and Washington, and agreed to rent 23 acres near Lorton from the District to build a multimillion-dollar incinerator that would generate electricity.

The Fairfax bureaucracy has outgrown the 12-story Massey Building in Fairfax City that currently houses the local government, and the county spends nearly $6 million a year to rent office space for its workers, according to county officials.

Herrity said he has changed his mind about supporting the government center because of the escalating price the county must pay for rental office space and because of the refusal of Fairfax City, an independent jurisdiction, to take action to ease traffic around the existing county government center by widening Rte. 123.

Moore blasted the joint venture proposal, calling it "a private deal with developers to avoid a referendum." She also attacked the Republican majority on the county board, which she said changed its stand on the issue for political reasons.

Her remarks prompted Republican Supervisor Thomas M. Davis III to retort: "You're welcome to join the party."

Davis, although he voted to go ahead with plans for the joint venture, has in the past opposed the new government center. Yesterday, he said he still has reservations about a joint venture.

"It's not a free lunch," he said. "You're taking a county asset the 183 acres of county-owned land and you're trading it in." He urged county officials to give Fairfax City an "ultimatum" on widening Rte. 123 before going ahead with the joint venture.

County officials say that if they moved out of their present rented offices, about a third of the office space in Fairfax City could suddenly be vacant -- a move that would have a severe impact on the city's economy.