Rozansky & Kay Construction Co., a locally-based developer, has announced the start of three new office projects in the metropolitan area.

The three projects, valued at $100 million, will total approximately 884,000 square feet of office space, according to company president Alan Kay. Next year, the firm plans another $200 million worth of new office space construction in the region.

The three current projects include Judiciary Center, a 350,000-square-foot structure located between 3rd and 4th streets and E and F streets NW, and two complexes in Montgomery County.

General Electric Credit Corp. and Bank of New York arranged a $42 million financing package for the Judiciary Center project.

Twinbrook Office Park, a 150,000-square-foot office complex rising on Rockville Pike in Montgomery County, is being built simultaneously with Holiday Inn's new 310-room hotel. Bank of America provided $52 million in financing for construction there.

And construction has begun on the first of four buildings that will eventually comprise 176,000 square feet of office space to be known as Montgomery Village Executive Plaza. The Old Stone National Bank of Connecticut is the source of $4.2 million in financing for the Gaithersburg undertaking.

The $200 million in new construction slated for next year will include the Bethesda Metro Center, consisting of a 400-room Hyatt Hotel, 375,000 square feet of office space and 40,000 square feet of commercial space. Also included in the plans for 1982 are a 340,000-square-foot office building downtown and a 600,000-square-foot office park in Prince George's County.

* The Braedon Cos. have leased 7,948 square feet at 1100 15th St. NW to the law firm of Goldberg, Fieldman & Letham for a total lease value of over $2 million. The firm specializes in public utility law.

* AKI/Automix Keyboards Inc. has taken occupancy of 3,700 square feet of space at 8545 Leesburg Pike, Vienna. The Smithy Cos., a mid-Atlantic real estate firm headquartered here, handled the transaction.

* This Wednesday the National Business League will hold groundbreaking ceremonies for its new headquarters building in Washington. NBL plans to erect a 130,000 square foot edifice on a 1 1/2-acre parcel at a cost of about $10 million. The facility will include meeting rooms, underground parking, a rooftop terrace and restaurant, and an open terrace at ground level. The Booker T. Washington Foundation, an affiliate of NBL, plans to move to the site, and member organizations of the National Council for Policy Review have been invited to consider occupancy in the new building, which will be the first office complex developed and controlled by a minority business organization.

* Arthur Rubloff Co. has arranged a 10-year lease between the National Recreation and Park Association (NRPA) and the Stone Tract Association for over 16,000 square feet at the Park Office Center in Alexandria. Rubloff agent Harry Pfohl negotiated the lease, which was in excess of $2 million. NRPA will occupy one full floor of the new facility with an option to expand.