Oct 1 (Reuters) - Amazon.com Inc said it expects to hire more than 70,000 full-time seasonal employees across its order fulfillment centers in the United States, a 40 percent increase from last year.

Amazon, which has about 88,400 employees, said it has converted more than 7,000 temporary employees in the United States into full-time employees so far this year.

"We're looking forward to converting thousands more after this holiday season," said Dave Clark, Amazon's vice president of worldwide operations and customer service.

Retailers typically hire seasonal employees in the weeks leading up to the holiday shopping season to work in stores and help in distribution and fulfilling online orders.

Amazon said its seasonal employees are eligible for health care benefits.

Amazon, the world's largest online retailer, is spending billions of dollars on expansion, which has taken a toll on its earnings.

It unveiled two new high-definition tablets last week with a unique on-screen helpdesk feature it hopes will give it an advantage over devices from rivals Apple Inc and Google Inc.