Fairfax County's 12,000 teachers and other public employes will not get cost-of-living salary increases this year matching those of federal workers, the Fairfax Board of Supervisors decided yesterday.

Despite an earlier commitment to keep county salaries within federal guidelines -- which on Aug. 31 raised the cost-of-living increase from 5 1/2 percent to 7 percent -- the board decided to defer action at least until December, well after the Nov. 6 election.

"I can't believe what I'm hearing," Supervisor Audrey Moore (D-Annandale), said. "I think we have an obligation to the people to make a decision before the election . . . Both the taxpayers and the employes have a right to know where we stand."

But the board, by an 8-to-1 vote, supported the deferral motion of Supervisor Joseph Alexander (D-Lee). Alexander said he and his colleagues needed to wait until December to see if the county would be taking in enough revenues to pay for a supplementary increase from the present 5.15 percent to 7 percent.

The increase to 7 percent, which has already been endorsed by the school board, would cost the county about $3.3 million for the teachers and about $1.5 million for other employes, if made retroactive to Oct. 1.

The supervisors' deferral was immediately attacked by the Fairfax Education Association, which counts most of the county's 7,000 teachers as members.

"Fairfax educators will get their piece of the board [of supervisors]," association president Gerry Gripper said, referring to the upcoming election involving all eight supervisor districts and the at-large chairman.

Gripper said "500 to 600" members have volunteered to support association-endorsed candidates, some of whom voted to defer the cost-of-living supplementary increase. One of the supervisors targeted for defeat by the association is Moore.

The supervisors decided not to grant an immediate increase after school officials said their system would need an extra $3.5 million to cover higher energy costs and reduced federal aid. That money would have to be provided by the supervisors ahead of any funds for a pay raise, school board vice chairman Ruth Dell said.

"That means we'll have to come up with$6 million-plus for the schools and $1.5 million for county employes," Republican board chairman John F. Herrity said in support of deferral.

The supervisors did make one symbolic gesture toward a pay raise for teachers and public employes by a narrow vote of five ayes to four abstentions. They said the new board, which takes office Jan. 1, should give a 7 percent increase next year along with a 1.5 percent catch-up. But that request is not binding on the new board.