The Fairfax County Board of Supervisors, angry at rising Metro transit costs, voted yesterday to begin operating its own public bus system and to withhold $6.3 million it owes Metro.

Several supervisors said the unanimous decision to spend more than $4 million for 26 buses to replace Metrobus service near the county's first subway station was a major step toward dismantling Metro's extensive regional bus network.

The proposed county bus system around the Huntington Metro Station south of Alexandria would reduce Fairfax's annual $24 million payment to Metro by more than $600,000, according to a consultant's study.

Two hours after their vote to eject Metrobuses from southeastern Fairfax, the supervisors voted 8 to 0 with one abstention to withhold their quarterly $6.3 million payment to Metro. The supervisors said they will not forward the money, which was due Friday, until the Metro board approves a fare increase, which would decrease the subsidies local governments must pay.

Richard Page, Metro's general manager, said Fairfax's decision to withhold the payment will reduce its influence. "Nobody likes to be threatened or be blackmailed, and I think this is a childish way to do business," he said.

"We're trying to send a message that we're not very happy over here in Fairfax," said Supervisor Martha V. Pennino, pointing out that no Metrorail stations have opened in the county. "It's fairer for those who ride the Metro to pay the costs rather than making taxpayers who don't ride subsidize it," she said.

Metro fares were originally scheduled to increase Jan. 1, but the Metro board postponed the increase at least until April because it feared that higher fares would accelerate a decline in Metro's ridership. Fairfax will have to pay Metro an extra $518,000 if the fare boost is delayed until July 1, county officials said yesterday. "They Metro have thrown everybody's budget into a tailspin," Supervisor Marie B. Travesky said.

Supervisor Joseph Alexander abstained yesterday from the vote to withhold the payment. Earlier, as the county's representative to the Metro board, he supported the delay in increasing fares, and he has taken some heat from his Fairfax colleagues because of it. "That was an act of statesmanship, and I'm sorry to see it's getting wrung around his neck now," Page said yesterday.

Alexander, whose vote was crucial to the delay, said he wanted to maintain good relations with the other jurisdictions, in part to boost Fairfax's chances of getting rail service soon.

"That's what I tried to tell the county board," Alexander said. "I made every effort to tell them I need help at Metro , and this isn't going to help. Obviously, they were in no mood to listen."

The Fairfax board's decision to buy its own buses was the outgrowth of the county's longstanding unhappiness with Metro's labor costs. A $58,000 consultant's study said the county can save "substantial amounts of money" by operating its own buses around the Huntington station, with increased savings as the county takes over more Metrobus routes.

"Some of us feel a large Metrobus system is not the best way to go," Travesky said. "It never was, it was foisted on us. But there has to be an orderly way of proceeding to dismantle the system."

The system would be privately run under contract with the county, but the drivers would be public employes and therefore, some county officials said, prohibited under Virginia law from joining labor unions. County supervisors blame Metro's rapidly increasing costs on the system's union contracts, with their fringe benefits and limits on part-time workers.

Other Metro jurisdictions have taken steps in the same direction. Montgomery County's Ride-On program currently operates 74 buses in Silver Spring and 19 in Gaithersburg, with 52 more buses on order for service in Rockville and Bethesda.

Jenny Leary, Montgomery's assistant chief of transit services, said her county believes Metro has a limited role to play in providing future bus service. "We still view them as a regional carrier operating on the trunk lines," Leary said, meaning Rockville Pike, Connecticut Avenue, Colesville Road and Georgia Avenue.

Alexandria has hired the same consultant used by Fairfax to study the cheapest and best way to provide bus service, and Prince George's County is planning to contract with private companies on some routes. The District has begun operating its own buses on a few routes.

Fairfax County's action potentially is more radical than those taken by other jurisdictions, however, because the county's routes will substitute for, rather than supplement, Metro's current routes.

"What we've got is a replacement system," Pennino said. "We've been talking a long time about what's before us today . . . . I'm for getting on with it."