Wal-Mart Stores Inc , the world's largest retailer, said on Tuesday that it supports President Barack Obama's push to require large employers to offer health insurance to workers.

We are for an employer mandate which is fair and broad in its coverage, stated a letter addressed to Obama and signed by Mike Duke, the chief executive of Wal-Mart; Andy Stern, the president of Service Employees International Union and John Podesta, the CEO of the Center for American Progress.

Wal-Mart, the nation's largest private employer, also said separately that the mandate should cover as many businesses as possible, and cover part-time and full-time employees.

Any alternative to an employer mandate should not create barriers or disincentives to hiring workers with disabilities, entry level employees, or people from low income families. said Leslie Dach, Wal-Mart's executive vice president of corporate affairs and government relations, in a statement.

Wal-Mart has drawn criticism from labor groups, who have accused it of mistreating employees and not offering adequate health care coverage. Former CEO Lee Scott worked to counter those critics before he retired from his role as CEO earlier this year.

Meanwhile, Obama has stepped up his push for health care reform. The president has left much of the details of health reform to Congress, but he has told U.S. lawmakers he is open to requiring larger companies to provide coverage for employees while exempting smaller businesses.

(Reporting by Nicole Maestri; Editing by Tim Dobbyn)