A Fairfax County condominium law has been challenged in court by the only developers the county has attempted to block from converting a rental apartment complex.

The owners of the Arrowhead Apartments, a community of 343 homes near Tysons Corner, have sued the Board of Supervisors in Circuit Court, claiming the board had no legal right to keep Arrowhead from becoming a condominium. The board denied the conversion last month after many tenants protested the plan.

The Virginia General Assembly already has placed strict limits on the ability of Northern Virginia governments to regulate conversions, which have been common in Arlington and were spreading to Fairfax before the current recession slowed real estate activity. The lawsuit, filed by apartment owners Stanley H. Rosensweig, Charles S. Faller Jr. and the George C. Marshall Limited Partnership, seeks to limit further the board's power.

"If they are successful, it will seriously undermine the board's legislative discretion," said Supervisor James M. Scott, whose Providence District includes Arrowhead.

Fairfax has no specific authority to prevent a condominium conversion or to demand concessions for current tenants. But the board reserves the right to forbid conversions if apartments are not brought up to current zoning standards. In the past, the supervisors have used their zoning powers to extract concessions for tenants.

That practice is challenged in the Arrowhead suit, which was prepared by former Arlington County Attorney Jerry K. Emrich. The problems cited by the board, which included parking and traffic issues, "are not related to the condominium conversion, nor are they within the authority of the board to impose," the lawsuit states.

The county's authority also was challenged in a bill introduced by Del. John H. Rust Jr. and approved by the General Assembly this year. The bill, which Emrich said merely reaffirmed existing law, forbids counties from using their zoning laws as a way to extract concessions from condominium developers.

Scott said the bill limited but did not remove the county's authority. "Even with the Rust bill, we do have some discretion," Scott said.