Wal-Mart Stores Inc. is under increasing attacks for what its critics call inadequate health care coverage for its 1.3 million workers and is thus preparing to sell generic prescription drugs to its employees and customers at reduced prices, according to published reports.

The world's biggest retailer is expected to announce a test that will involve reduced prices on generic drugs, according to The New York Times. The Wall Street Journal said Wal-Mart would announce "a low price strategy" for generic drugs sold at its pharmacies.

Both reports cited people familiar with its plans who were not identified further.

Wal-Mart executives declined to comment Wednesday on what the plan entails. The announcement is being made in Tampa, Fla.

The Times said the retailer will sell generic versions of about 300 widely prescribed drugs for as low as $4 for a standard prescription. On average, it said generic drugs cost between $10 and $30 for a 30-day prescription.

Wal-Mart will test the lower prices first in the Tampa area and, depending on response, may expand the program around the state and the country, the Times report said.

The initiative would be the fourth time since last October that Wal-Mart has moved to improve health benefits.

Wal-Mart's recent moves to improve its health care plan include relaxing eligibility requirements for its part-time employees who want health insurance, and extending coverage for the first time to the children of those employees. Part-time employees, who had to work for Wal-Mart for two years to qualify, now have to work at the company for one year. This year, Wal-Mart also expanded a trial run of in-store clinics, aimed at providing lower cost non-emergency health care to the public.

Last October, Wal-Mart offered a new lower-premium insurance aimed at getting more of its work force on company plans.

But critics argue that Wal-Mart's coverage calls for a deductible that requires workers to pick up the first $1,000 in medical expenses, and the deductible rises to a maximum of $3,000 for families.

Union-backed Wake Up Wal-Mart, one of its most vociferous critics, have called upon Bentonville, Ark.-based Wal-Mart to offer better health care coverage and higher pay to employees.

Critics contend that the company's benefits are too stingy, forcing taxpayers to absorb more of the cost as the workers lacking coverage turn to state-funded health care programs.

This past summer, Wal-Mart won a successful fight against a first-of-its-kind state law that would have required the retailer to spend more on employee health care in Maryland. A federal judge ruled in July that it was invalid under federal law. But other states are considering similar legislation aimed at the company.