Workers at a Ford stamping plant in the United States have agreed to work rule and other changes that will make the plant more efficient.

Ford spokeswoman Marcey Evans told The Associated Press that United Auto Workers members at the Woodhaven stamping plant south of Detroit agreed to the changes in what is called a "competitive operating agreement".

UAW Local [branch] 387 represents about 1,500 workers at the plant, which makes door panels, fenders, floor pans, hoods, quarter panels, roofs and tailgates.

Evans reportedly deferred comment on specifics of the agreement to the UAW but union officials familiar with the pact did not immediately return calls made by the news agency.

The agreement, which comes while the current UAW contract with Ford is in effect, allows Ford to offer more buyout packages to workers at Woodhaven, The Associated Press noted.

Evans reportedly confirmed that additional buyouts are part of the agreement with the union branch, which she said "will help facilitate the efficiencies they wanted to gain at their plant."

She told AP about 150 workers have accepted buyouts so far at Woodhaven, but would not say how many more workers would be offered packages.

Union locals at plants in Chicago, suburban Cleveland and other locations have reached similar agreements, Evans told AP. But she also would not say whether Ford would seek similar pacts elsewhere.

"I can say that we're pleased when factories are looking at steps to become more efficient and take measures to become more competitive," she told The Associated Press.