A delegation of U.S. civil and labor rights groups will depart for Mexico City on Sunday hoping to urge the Mexican government to pressure Wal-Mart Stores Inc. (NYSE:WMT) to end what they say is severe labor exploitation in the supply chain of the world’s largest retail operation.

“While it may be hard for some of these suppliers [to meet price demands], Wal-Mart is making huge profits. Money needs to come down from this mega-corporation so that small suppliers aren’t squeezed to provide ever more product at lower costs that can lead to forced labor and other severe labor exploitations,” said Jacob Horowitz of the New Orleans-based National Guestworker Alliance, which is helping organize the trip.

National Organization for Women President Terry O’Neill, head of Worker Rights Consortium Scott Nova and other civil and labor rights advocates are planning to meet with representatives from Mexico’s Foreign Relations Secretariat and rights groups south of the border on Sunday and Monday.

The meeting comes as Mexico is implementing a series of broad reforms to its labor law, including bolstering the government’s obligation to ensure its citizens working abroad are treated in compliance with local and international agreements on workers’ rights. How Mexico would confront a major, publicly listed U.S. company is unclear. Wal-Mart’s largest foreign subsidiary is in Mexico and was faced earlier this year with a bribery scandal.

Foreign nationals are allowed to enter the United States on H-2 visas, allowing them to work legally as seasonal workers. The H-2B visa allows laborers to enter the non-agricultural job market in areas where employers claim they cannot find American citizens to perform the duties. Common jobs include seasonal hotel housekeeping work, landscaping, forestry and seafood processing.

“We know the Mexican government is concerned about the treatment of its citizens that work abroad, but they may not be aware of how egregious the extent to which labor practices affect Mexican guest workers,” Nova said. “The primary focus is on Wal-Mart, which is by far the most powerful player. It claims to take responsibility with respect to the rights of the workers. All of this is part and parcel of a system that feeds into the Wal-Mart supply chain from which it profits.”

Wal-Mart would not comment on the story, but it says it holds its suppliers to ethical and legal standards. In June, with the help of rights advocates, seafood processors from Mexico complained to the Dept. of Labor about abusive practices at C.J.'s Seafood of Breaux Bridge, Louisiana. Wal-Mart responded by suspending its relationship with the family-owned company pending a federal investigation. The Dept. of Labor ordered CJ’s to pay $213,742 in fines and civil penalties, including paying $76,608 in back wages for paying the workers less than the federal minimum wage. C.J.’s has since closed down its operations.

But groups like the NGA say Wal-Mart only reacts in this manner when a case makes waves in the media or when the federal government reacts first, rather than proactively rooting out abuse. Rights advocates say the company should also inform the public about where in its supply chain these workers are being utilized.

“We’ll be calling on the Mexican government to demand more transparency in the WMT supply chain,”  Horowitz said. “The Mexican government has a direct interest given the forced labor that has come to light with C.J.’s involving its nationals. They have an interest and they have a responsibility.”

Alejandra Ancheita, of the Mexico City-based Proyecto de Derechos Económicos, Sociales y Culturales, A.C. (ProDESC) said the delegation is coming at a fortuitous time as the country is focused on a series of broad reforms to its 40-year-old labor law.

While some of these articles are controversial -- especially as they pertain to allowing Mexican companies to hire part-time hourly workers and utilize temp agencies -- changes to the labor law that bolster the government’s responsibility to ensure its workers abroad are treated fairly is likely to easily pass. The changes include requiring employers to submit contracts that outline various assurances that guestworkers will be treated equally to local hires and be informed of their rights.

“We would like to see a new perspective and new relationship with the Mexican government so it understands that having an H2A or H2B visa is not a guarantee of protection for these workers,” Ancheita said by telephone. “We hope to relay that message to them.”