The Fairfax County Board of Supervisors plans to decide tonight whether to proceed with a controversial $3.3 million plan to convert part of a run-down apartment complex into federally subsidized public housing.

The issue, under consideration for five stormy years, involves old arguments concerning where and how public housing should be established and what the county's role should be in assuring the availability of housing for moderate-income tenants.

Under the plan, the county would pay $330,000 and the U.S. Department of Housing and Urban Development would pay the rest to renovate 119 of the 512 two- and three-bedroom units in Jefferson Village on Route 50, according to Walter B. Webdale, director of the Fairfax County Redevelopment Housing Authority. Then the county would convert them into housing for low-income families whose annual incomes tend to fall between $12,000 and $20,000, he said.

The other 393 units, Webdale said, would be purchased by a private developer with $9.2 million in loans obtained with the help of the county, with the stipulation that 20 percent of the units be rented to those with moderate incomes in the $20,000 range. The proposed developers, Rosenberg Freeman and Associates and Housing America Inc., also would be required to meet the county's rehabilitation specifications.

Marshall B. Coyne, proprietor of Washington's Madison Hotel and the current principal owner of Jefferson Village, has filed an application with the county to convert the complex into condominiums if he dosen't sell it, county officials said.

James M. Scott, county supervisor representing the Providence District, where Jefferson Village is located, said the county plan "is the only chance to protect a substantial number of the residents from displacement and to ensure renovation in a timely fashion."

Residents, many of whom are Asian and Hispanic refugees, have long been troubled by maintenance problems ranging from failing appliances and peeling paint to severe drafts and lapses in heat and hot-water service, said Malik Khan, resident and co-chairman of a task force appointed by Scott to study the proposal.

"To say that it is a little run-down is a very kind understatement," said Khan. "It's an eyesore."

Kahn said the task force has endorsed the plan.

Others, like county board Chairman John F. Herrity and residents living near Jefferson Village, strongly oppose the plan.

"I doubt if I am going to support this scam," said Herrity. Putting 119 public housing units in one cluster violates county guidelines that call for limiting the number of public housing units in one location to 50, he said.

In addition, Herrity said the 393 privately owned units, which would rent for about $580 a month, would be too expensive for current residents.

Most residents pay about $400 a month, and for some that is nearly half their income, Webdale said.

Whether the project is converted to condominiums or to a combination of private and public housing, Herrity said, "many people who live there will be displaced.

"For the county to pay $330,000 for overpriced housing units in one place is not good public policy, especially when it isn't going to help the people of Jefferson Village," he said.

Scott contends that the county plan would "at least save some of the residents from displacement." If a condominium coversion takes place, he said, very few of the residents could afford to stay.