Amazon is introducing two new versions of its Kindle electronic reader, including a model that sells for $139, its lowest price yet according to The New York Times.

The $139 Kindle will be Wi-Fi only, connecting to the online Kindle store by wireless instead of 3G cellular networks like the previous Kindles, the Times said.

The other new Kindle will replace the basic Kindle 2, which was listed as “temporarily out of stock” on Wednesday at Amazon.com.

The Times said the new basic Kindle will sell for the same price, $189, as the current model.

It said both new Kindles are smaller and lighter than the current versions and feature higher resolution screens and crisper text.

Amazon is cutting the price of the Kindle and revamping the line as it faces a threat in the e-reader market from Apple’s iPad and companies like Sony and bookstore Barnes & Noble, which also offer e-readers.

“The hardware business for us has been so successful that we’re going to continue,” Amazon founder and chief executive officer Jeff Bezos told the Times in an interview.

“I predict there will be a 10th-generation and a 20th-generation Kindle. We’re well-situated to be experts in purpose-built reading devices,” he said.

Mr Bezos said not to expect a colour Kindle soon. Colour was “not ready for prime time,” he said.

Apple’s cheapest iPad costs $499 and features a colour e-reader compared with the black-and-white Kindle, which is devoted exclusively to digital books.

Barnes & Noble sells a version of its e-reader, the Nook, for $149 while Sony’s cheapest e-reader is $150.

The new Kindles, which will ship on August 27, weigh about 15 per cent less and are 21 per cent smaller than the current basic model, the Times said.

Amazon also offers a large-screen model, the Kindle DX, which costs $379.