Braced for a potentially bitter fight with the local business community, Fairfax County Supervisor Thomas M. Davis III will begin a push tomorrow for legislation that would require nonsmoking sections in many restaurants in the county.

Declaring that the county's bid to encourage restaurants to separate smokers and nonsmokers voluntarily had failed, Davis said Friday that a law requiring a separation is the only way to protect the rights of nonsmokers.

"This is not an antismoking ordinance," Davis said. "It simply recognizes that nonsmokers have rights, too."

The proposed ordinance -- which is already opposed by the chairman of the Board of Supervisors, the Northern Virginia chapter of the Virginia Restaurant Association and the tobacco industry -- would require any restaurant in Fairfax County with a seating capacity of 75 or more to prohibit smoking in certain sections of the building.

In the cases of single-room restaurants, the owner would be required to use plants and other objects to separate smokers from nonsmokers.

Davis said that only about 25 percent of Fairfax County restaurants have voluntarily created no-smoking areas, despite the county government's requests last year that they do so.

He needs the support of at least four of his fellow supervisors at tomorrow's meeting of the board to schedule a public hearing on the issue. The meeting will begin at 9:30 a.m. in the Massey Building in Fairfax City.

Board Chairman John F. Herrity said he opposes Davis' plan and might even vote against a motion to set a date for a public hearing on the issue.

Herrity said he has "serious reservations about trying to pass laws governing people's habits." He added that the proposal also would unfairly restrict businesses.

Preston H. Nebel, president of the local chapter of the Virginia Restaurant Association, said the suggested ordinance would force "major remodeling" demands upon many restaurant owners. "We're in business to make money," he said. "We're opposed to the government telling us how to run our businesses."

Similarly, the tobacco industry is "opposed to any type of mandatory allocation of space" for nonsmokers, said John H. Rust Jr., an attorney for the Virginia Tobacco Institute.

"This should be a matter of freedom of choice," Rust said, adding that the proposed ordinance "would be unmanageable for the restaurants and the patrons."

Davis said he is not surprised by the intensity of the opposition to his plan. "It is not going to be an easy fight," he said. "There's going to be a lot of pressure by the business community on a lot of the board members."