June 11 (Reuters) - Thousands of Amazon.com Flex drivers classified as contractors filed arbitration claims on Tuesday, , their lawyer told Reuters, saying they should be treated as full employees.

About 15,800 drivers have submitted claims with the American Arbitration Association, seeking compensation from Amazon for unpaid wages, overtime and work-related expenses such as mileage and cellphone use, the lawyer said. Other 453 similar cases are already being litigated.

Amazon does not provide Flex drivers with 10-minute rest breaks when their shift lasts longer than 3.5 hours, one of the drivers said in its arbitration claims.

In response to this claim, an Amazon spokesperson told Reuters that "the majority of Amazon Flex delivery partners finish their delivery blocks early."

Another claim said that Amazon does not provide 30-minute meal breaks for drivers who work more than five hours a day, whereas another claim alleged that Amazon fails to provide itemized wage statements required by California law.

"The Amazon Flex program gives individuals the opportunity to set their own schedule and be their own boss, while earning competitive pay," an Amazon spokesperson told Reuters.

Amazon Flex, which works like on-demand ride-hailing service Uber, handles speedy deliveries of common household goods to customers through programs such as Prime Now and Amazon Fresh. (Reporting by Nilutpal Timsina in Bengaluru; additional reporting by Angela Christy; Editing by Alan Barona and David Gregorio)