The iPad mini, equipped with a high-resolution “Retina” display, is now available to order from the Apple online store with prices starting at $399.

Supplies of the new device may well be limited. Philip Schiller, Apple’s senior vice president of worldwide marketing, hinted as much when he said “we’re working hard to get as many as we can in the hands of our customers”.

Rhoda Alexander, director of tablet research at IHS electronics and media, is quoted in the UK’s Daily Telegraph as saying the supply of the Retina Mini is going to be “ridiculously tight in the fourth quarter”.

The quiet launch of the new device comes after numerous reports of supply problems surrounding the LCD display (manufactured by LG Display and Sharp). Analysts had not expected the new tablet to be available until the end of November.

Already available on the iPad Air 9.7-inch screen, the Retina display brings all the pixels from that device (2048×1536) to the 7.9-inch screen of the new iPad mini.

“The response to iPad Air has been incredible, and we’re excited for customers to experience the new iPad mini with Retina display,” purred Schiller.

The 16GB Wi-Fi model carriers a suggested retail price of $399, going up to $499 (32GB), $599 (64GB) and $699 (128GB).

The Wi-Fi+cellular models start at $529 (16GB), rising to $629 (32GB), $729 (64GB) and $829 (128GB).

The Retina display version of the iPad mini is powered by a 64-bit A7 chip (which also powers the new iPhone 5s). It offers up to four times faster CPU performance and up to eight times faster graphics performance than the previous generation iPad mini.