A dispute over wages for low-income foreign workers is holding up final agreement on a comprehensive immigration proposal being developed by a bipartisan Senate group, people with knowledge of the deliberations said.

The AFL-CIO and Chamber of Commerce have agreed to a general framework that would add up to 200,000 new visas per year for a new guest worker program for foreigners.

The number of visas would fluctuate based on recommendations by a new federal bureau charged with analyzing employment data and employer needs. The foreign workers would be able to switch jobs on their temporary visas and some would be granted a chance to pursue permanent residency and, potentially, citizenship under certain conditions.

How much those foreign workers are paid, however, is still being negotiated, said the sources, who asked to be anonymous because the negotiations are ongoing.

The Chamber has pushed for the workers – who would include maids, waiters, child care workers, home nannies and meat packer -- to be paid one step below the median hourly wage scale in their respective industries. But the labor union wants them to be paid one step higher than the median. In the case of a waiter, for example, the difference would be between $8.93 per hour (or $18,600 a year) and $10.61 per hour ($22,100), according to the sources.

Union officials are concerned that paying foreigners lower wages could drive down median wages for all employees.

“The labor movement’s driving concern is to make sure these are decent jobs with decent pay,” said one person sympathetic to the labor position. “We’re not trying to make anyone rich here.”

Randy Johnson, the Chamber's senior vice president of Labor, Immigration, and Employee Benefits, said in a statement:

"Our position has consistently been that the wage issue should be resolved by sticking with current law.  Any temporary worker program would require that an immigrant worker be paid the greater of actual wages being paid to comparable American workers or the prevailing wages.  In some cases, the prevailing wage determination by the U.S. Department of Labor concludes that the employer’s actual wages are less than prevailing.  If DOL so determines, then the employer must pay the prevailing wages in order to hire a foreign worker.  The requirement to rely on a DOL prevailing wage determination has been in US immigration law since 1990.  All the business community is saying is that we want to retain this standard."

The bipartisan Senate group, which includes four Democrats and four Republicans, hopes to finish negotiations Friday, which would allow aides to write the legislative bill over the two-week Easter break. The bill would be unveiled after the Senate resumes work April 8, senators said.

An expanded guest worker program is among the major new components in the Senate group’s bill, which is expected to be a template for a possible deal between Congress and the White House. Other likely components are a path to citizenship for the nation’s 11 million illegal immigrants, reductions to some categories of family visas, increases in visas for high-tech workers and increased border control and work-place security.