Carpenters joined cement and metal workers in walking off the job Wednesday at the World Trade Center site, the third day of job actions over pay cuts.
The cement workers, members of the Concrete Workers District Council who have been without a contract since July 1, have stopped working at the site in protest of a proposed 20 percent pay cut.
Louis Coletti, president of the Building Trades Employers' Association, which is bargaining with the Concrete Workers District Council, said any cut would be for new residential or hotel construction and wouldn't affect the workers in their job at the World Trade Center site.
"No one on that site is being asked to take a pay cut," he said, adding that discussions were continuing between the sides.
He said the cuts were necessary for new hotel or residential jobs because nonunion competition in those sectors has grown. The cuts wouldn't affect other sectors, like schools, hospitals or commercial buildings, he said.
The Concrete Workers District Council declined to comment.
Cement worker Michael Pappalardi was among about 100 laborers participating Wednesday morning. He said they've received "no word, good or bad," from union officials, other than to "stand strong and wait it out."
By early afternoon, the area where stopped workers have congregated stood empty.
The Port Authority of New York and New Jersey, which owns the site, has said the work stoppage has no impact on the memorial, which is scheduled to open on the 10th anniversary of the attacks.
Thousands of workers around the city are members of the union.