The service billed as 'the Netflix of books' is currently only available in the US

Amazon has launched a subscription e-book service that gives American customers unlimited access to more than 600,000 Kindle titles for $9.99 a month.

Users can sign up for a free 30-day trial to Kindle Unlimited, with the service also including 2,000 Audible audiobooks as well as free three-month subscription to the wider Audible service with some 150,000 titles.

There are some limits to the service, with any download e-books locked from use outside the Kindle app by DRM (digital rights management) technology, and with only 10 books allowed to be ‘borrowed’ at any one time.

The selection includes classics and best-sellers such as Animal Farm and A Life of Pi as well as popular series such as Harry Potter, Lord of the Rings, and Hunger Games.

The move comes at a time when the retailing giant is still in a battle with French publisher Hachette over e-book prices. Amazon wants to be able to discount books published by Hachette whenever it likes and in order to force the company to agree has been throttling its sales by inflating the shipping time on its titles to a “minimum of 2-3 weeks”.

The launch of Kindle Unlimited will also threaten the start-up Oyster, which has also been offering a subscription e-book service for $10 a month. Like Amazon’s service, Oyster is also available as an app for iOS and Android devices.