The nation's largest retailer announced it was expanding its existing 10% employee discount to cover nearly all groceries, including dairy, frozen foods, dry goods, meat and seafood all year.

"We know the impact this discount has for so many of our associates and their families," Kieran Shanahan, Walmart's Chief Operating Officer, said in a LinkedIn video. "We've made (the discount program) simpler, more accessible and something that more associates and their families can take advantage of."

Previously, the 10% Walmart Associate Discount Card was good only for fresh produce and general merchandise, such as clothing and toys, but expanded to other foods only during the holiday season. It will now be in place for food and merchandise year-round, Shanahan said, starting immediately.

The change, according to a memo from Walmart chief people officer Donna Morris obtained by CNBC, will cover some 1.6 million U.S. employees who will qualify for the discount 90 days after their hiring date. Employees with more than 20 years of service receive the discount for life.

The discount covers 95% of the regularly priced items in the store, according to the memo.

The expansion puts Walmart more in line with other retail discount programs. According to RetailDive, Target employees get 10% off "most" merchandise and an additional 20% off food and wellness products. Kroger offers 10% off its private-label brands and Trader Joe's and Whole Foods both offer workers 20% off.