Some 35,000 Mexicans, most aged between 60 and 74, packed groceries at Walmart's stores and other chains in Mexico through a government-backed volunteer program, earning just tips, before the pandemic.

After pressure from workers, President Andres Manuel Lopez Obrador said last week that he would speak to the retailer about a reported decision to not allow them to return.

"Where the epidemiological traffic light is green, older adults who already have their full COVID-19 vaccination schedule are allowed to resume their work as volunteer packers," the retailer said in a statement.

(Reporting by Daina Beth Solomon, writing by Stefanie Eschenbacher; editing by Jane Wardell)

By Daina Beth Solomon