Wal-Mart Stores, the world’s biggest retailer, is betting big on e-commerce business as part of its efforts to compete with Amazon, the world’s largest online e-commerce retailer. According to a report by Bloomberg, Wal-Mart announced this week that it is expanding its Online Grocery Delivery service to two new cities in a partnership with Uber Technologies. In a blog post on Monday, the retailing giant said that it is offering consumers in Orlando and Dallas to shop online for groceries and then get deliveries via Uber for a $10 fee.

Wal-Mart online grocery business

Wal-Mart is the largest grocer in the United States with annual sales of around $170 billion. The retailer is now testing different ways to boost online grocery sales.

The retailing giant launched its online grocery delivery business in 2013. Last year, the retailer partnered with Uber to test an online grocery delivery service in Phoenix. The service via Uber was later expanded to three more cities including Denver, San Jose, and Tampa. Now with the addition of Orlando and Dallas, the service is available in six U.S. cities.

Mike Turner, vice president of e-commerce operations at Wal-Mart, said in a blog that the retailer has been "testing delivery in a number of ways" in key markets across the U.S.

to supply fresh groceries in a quick way.

Wal-Mart’s e-commerce push

The retailing giant is aggressively reshaping its digital and mobile business in a bid to compete with Amazon, eBay, and brick-and-mortar competitors.

During the last 12 months, the company made several improvements to its online marketplace, launched new services to support e-commerce business and acquired a number of e-commerce companies including Jet.com, ModCloth, ShoeBuy, and Moosejaw.

The retailer is now trying to attract customers through free same-day pickup service at stores, online grocery customers’ car pickup, and discounted in-store pickup options. Earlier this year, the retailing giant reduced its free 2-day shipping minimum to $35 as well as increased the number of products available for free shipping.

Wal-Mart’s massive investments in its e-commerce operations seem to be paying off. During the first three months of this year, the retailing giant reported a 63% increase in its e-commerce sales, compared to a 29% increase in the same period last year. The company now has 50 million items on its website, compared to 10 million items last year.