Reports from Korea suggest that the delay in getting the iPad mini with Retina display could be down to issues with the Retina displays themselves. It is said that the TFT LCD panels are experiencing burn-in issues.

Apple has always said that the iPad mini with Retina display will be released "later in November" and after the iPad Air has hit shops. The Air was released in the US and UK last Friday, 1 November, but the mini has still not been given an actual release date.

READ: iPad mini with Retina display pictures and hands-on

It is not know how many panels are suffering from the issue but the Korea IT Times claims that the problem is severe enough for Apple to consider switching its supplier to rival Samsung. At present, it's main suppliers are LG Display and Sharp.

The burn-in issues are said to be not visible to the naked eye, but do not pass the particular technological standards of Apple.

They are caused by the drastic reduction of the pixel size. The iPad mini with Retina display features the same 2048 x 1536 resolution as its 9.7-inch stablemate, but crammed into a 7.9-inch screen.