Congressional budget writers yesterday approved the first $35 million installment toward building a giant Food and Drug Administration complex that boosters hope will catalyze development in the urban neighborhoods along the Montgomery and Prince George's border.

A House-Senate budget conference committee approved $29 million for a 100,000-square-foot office building for the FDA's Center for Drug Evaluation and Research at the former Naval Surface Warfare Center in White Oak. It also agreed on $6 million to design a proposed $600 million FDA headquarters campus over the next decade.

Since the late 1980s, area leaders have dreamed of consolidating FDA facilities in the Maryland suburbs in order to draw private biotechnology firms, research labs and computer companies to the region. Now they have surmounted a decade of setbacks, starting with recession and continuing with Congress's anti-regulatory wave of 1994 that held up funding.

"This is the critical first step to consolidation of FDA at White Oak," said Sen. Barbara A. Mikulski (D-Md.), a budget conferee who led Senate funding for the agency.

Area lawmakers struck a deal with Republican committee chairmen to include the FDA site as virtually the only new federal building funded under a $13.7 billion appropriations bill covering the Treasury, Postal Service and general government.

The measure is set for final passage in both chambers by month's end, with a House vote possible as early as last night, according to Rep. Albert R. Wynn (D-Md.), who supported the project inside his district.

Rep. Steny H. Hoyer (D-Md.) said that although the amount approved was less than the $56 million requested last winter by the Clinton administration, the funds demonstrate Congress's commitment to building the campus over the next 10 years.

The initial building for the Center for Drug Evaluation and Research will consolidate 100 workers from five locations in the Washington region.

Over the next 10 years, the General Services Administration proposes to centralize 1,600 FDA workers from 21 sites into a 2.1 million-square-foot complex on 130 acres, saving $200 million in lease costs.

Of the 530 acres remaining at the White Oak site, Montgomery County will use 60 acres for parks and recreation, the Air Force will keep 64 acres to operate a wind tunnel and federal officials will decide the future use of 406 acres.

"This is what we've been waiting for," said Montgomery County Executive Douglas M. Duncan (D). "There will be fights ahead, but once they make that initial commitment to move the FDA there, it's difficult to say, no."

CAPTION: Sen. Barbara A. Mikulski (D-Md.) cited the "critical first step to consolidation."