Amazon.com Inc. (Nasdaq: AMZN), the largest Internet retailer, said it will hire more than 50,000 seasonal workers at its U.S. fulfillment centers to meet winter holiday season demand, as more consumers favor online shopping.

"Temporary associates play a critical role in meeting increased customer demand during the holiday season, and we expect thousands of temporary associates will stay on in full-time positions," Dave Clark, vice president of Global Customer Fulfillment, said in a statement.

The Seattle-based e-commerce company did not say how many seasonal workers it hired for the 2011 holiday season, but said the plan to hire more than 50,000 is up slightly from last year.

Amazon currently employs 20,000 people at its 40 fulfillment centers across the country. The company said it expects thousands of seasonal workers to stay at Amazon in full-time positions after the holidays are over.

Retail spending is expected to grow by 4.1 percent this holiday season over last year’s, with shoppers spending $586.1 billion, according to the latest forecast from the National Retail Federation (NRF), a retail trade group. While that 4.1 percent is slower than last year’s 5.6 percent growth, it’s still faster than the 10-year average of 3.5 percent. Online sales in particular are expected to increase by 12 percent over the 2011 holiday season, to $96 billion.

For some retailers, the holiday season could account for one-third of annual sales. In 2011, holiday sales represented 19.5 percent of total retail industry sales.

The world's largest retailer, Wal-Mart Stores Inc. (NYSE: WMT), which is facing increased competition from online giants such as Amazon.com, is trying to cater to Web-savvy shoppers who are demanding more convenience.

Last week, the Bentonville, Ark.-based company said it had begun testing same-day delivery for online purchases in a handful of cities.

Meanwhile, Wal-Mart is also transforming its physical stores into extensions of its own online operations. The company now allows customers to pay for online purchases with cash, something Amazon can’t do.

In September, Wal-Mart announced that it will bring in 50,000 workers over the holidays, slightly more than it did last year.

Shares of Amazon.com Inc. (Nasdaq: AMZN) rose $1.26, or 0.52 percent, to $245.4 in Tuesday’s mid-day trading.

Holiday Hiring Roundup

The NRF predicts that retailers will add 585,000 and 625,000 seasonal employees in November and December, respectively -- roughly as many as they added last year, at 607,000.

Macy's, Inc. (NYSE: M), the second-biggest U.S. department-store chain, said it will hire around 80,000 seasonal workers this season, up 2.6 percent from last year.

Kohl's Corporation (NYSE: KSS) said it may hire about 52,700 holiday workers, up more than 10 percent from last year.

Toys R Us announced in late September that it expects to hire 45,000 workers over the holidays, 13 percent more than last year.

J.C. Penney Company, Inc. (NYSE: JCP) said it would add 40,000 temporary workers, 14 percent above the 2011 figure.

Target Corporation (NYSE: TGT) and Best Buy Co., Inc. (NYSE: BBY), on the other hand, will see a decrease in hiring over 2011 numbers.

Some of these jobs will translate into permanent employment, according to Hay Group. Target retained 30 percent of its seasonal workers last year, the firm said, and Toys R Us kept 15 percent.