(Reuters) -Walmart said on Tuesday it will expand online primary care benefits as part of its employee health insurance plan to its workers in 28 U.S. states.

The retailer employs more than 2 million people, according to a regulatory filing, and is the largest private employer in the United States.

Walmart said it has partnered with virtual healthcare services provider Included Health to expand its online primary care services, which are already available in 21 states.

The expansion comes months after Walmart announced plans to open new healthcare centres in the U.S. next year, as the company looks to expand its footing in the industry.

As part of the expansion, which kicks off this week, employees can access virtual care options, including digestive health and physical therapy as well as a few diagnostic tests at home, starting early next year, the retailer said.

Walmart said in a blog post it had observed an 11% reduction in the total costs of care for its employees and their families from a pilot run for its virtual primary care service.

The company added that most of its online health services offered as part of the plan were available at no additional cost.

(Reporting by Juveria Tabassum; Editing by Sherry Jacob-Phillips and Shweta Agarwal)