The agency quietly proposed last week that employers no longer be required to place ads for available agricultural jobs with print and broadcast media outside of where they plan to use the workers.
Advocates for farm workers say the change violates a 1986 federal law that requires employers to look for U.S. workers in designated multistate regions before they resort to hiring foreign workers.
Such a move could hurt farm workers who are U.S. citizens or legal residents, said Bruce Goldstein, executive director of Farmworker Justice Fund Inc.
"The Department of Labor is now saying the employers need not recruit beyond the local area. It will deprive U.S. farm workers of jobs that they want and that they need," Goldstein said.
Although some 70 percent of the estimated 2.5 million farm workers in the U.S. are believed to be undocumented, Goldstein said that leaves about 750,000 who are citizens or legal residents. Many of those workers migrate to their jobs.
A Labor Department spokesman did not immediately respond to a request for comment.
The proposed change was contained in a memo sent to state workforce agencies about the H2A visa program on Nov. 6. The Labor and Homeland Security departments proposed other changes to the program and are awaiting approval from the White House before releasing them for public review.
Congress failed to pass immigration reform this year, ending plans to provide workers - some already in the country illegally and some who would come from abroad - through guest worker and legalization programs.
Agriculture employers now fear they may not be able to find enough workers as the federal government steps up immigration enforcement.
The National Council of Agricultural Employers had asked the White House to end the requirement for out-of-state advertising in print and broadcast.
The group said the advertisements are expensive and unproductive. At times, the outlets where employers are told by the Labor Department to advertise already are running several dozen virtually identical ads, Sharon Hughes, the council's executive vice president, said in an August letter to President Bush.
Also the states where employers are required to advertise, considered traditional labor states, are states where in-state agriculture employers are also looking for H2A workers.
Hughes was traveling and could not be immediately reached for comment.