Fairfax County has chosen five developers to bid for the right to build the first phase of the proposed county government center near Fair Oaks Mall west of Fairfax City.

The developer selected to build the complex would receive as payment 116 acres of adjacent county-owned land for commercial and residential projects.

The five developers chosen as finalists for the potentially lucrative center are The Alan I. Kay Cos., Cadillac Fairview Urban Development Inc., The Donohoe Cos. Inc., The Charles E. Smith Cos./The Artery Organization Partnership, and Turner-Harwood Ventures in Association with the Fair Hills Assemblage. The firms must return their proposals to the county by June 30.

The new government center, which would be on a 100-acre tract south of the intersection of Rtes. 50 and I-66, would encompass nearly 1 million square feet when finished and would include 4,230 parking spaces. The first phase of the project would cost about $67 million to build, including $10 million for parking, according to county estimates.

Officials said the county bureaucracy has outgrown the 13-story Massey Building in Fairfax City now used as the government center. The county spends more than $5 million a year to rent office space for workers and agencies who cannot be accommodated in the Massey Building.

In return for building the government center, the county would permit the developer to build up to 1.4 million square feet of commercial projects and 733,333 square feet of residential projects on the 116 adjacent acres.