WASHINGTON — The House passed a one-week extension of current farm law yesterday, hoping to give Congress more time to finish a multibillion-dollar farm bill that is stalled by a dispute over tax breaks.

Negotiations on the roughly $280 billion, five-year bill to expand agriculture and nutrition programs are in disarray with lawmakers from the House and Senate squabbling over how to pay for it. The White House says both the current House and Senate versions are too expensive and has threatened a veto if either one reaches the president’s desk with the spending intact.

House members object to several tax breaks in the Senate bill, including provisions to help owners of race horses, landowners who find endangered species on their property, and those involved in litigation about the Exxon Valdez oil spill.

The Bush administration has also objected to giving new money to farmers, especially when crop prices are high and farm country is in good shape. The bills passed by both chambers would expand subsidies for several crops and create new grants for vegetable and fruit growers.