A House and Senate conference committee agreed to cut federal funding for Metro construction during the next year to $180.5 million, which would be used to help complete the long-awaited Green Line spurs to Greenbelt and Anacostia.

The agreement, if approved by the full House and Senate, would represent a 10 percent reduction from the $201 million allotted to the transit agency for construction in the fiscal year that ended Sept. 30.

Metro had requested $250 million; the Reagan administration, which failed in earlier attempts to block federal financing of Metro construction, had urged Congress to limit Metro to $130 million this year.

Yesterday's congressional agreement "is important for Metro and important for the region because {the Washington area} is a mass-transit-dependent region," said Rep. Frank R. Wolf (R-Va.).

The Metro financing was one of several local projects included in the committee's mammoth $9.13 billion transportation appropriations bill. According to Wolf's office, the other projects, which will be cut an additional 4 to 5 percent, include:

$4.1 million for the last phase of improvements to Rte. 1 in Arlington, near National Airport.

$15 million for improvements to the Baltimore-Washington Parkway.

$500,000 for noise barriers along I-66 near the community of Falls Hill in Fairfax County.

$250,000 to update information used by the Metropolitan Washinton Council of Governments for transportation planning.

An unspecified amount for a study of ways to improve traffic flow on the Woodrow Wilson Bridge by adding lanes or decks or by building another bridge.