Apple is encountering production challenges in including fingerprint sensor to the iPhone 5S and upgrading the iPad Mini 2 display to Retina technology, which likely will delay the devices' release dates to the last quarter of 2013.

In a new note to investors, KGI Securities analyst Ming-chi Kuo has indicated that most of Apple's 2013 gadget line up will be delayed "will begin shipments later than our previous expectation and market consensus."

Mr Kuo based his new assessment to "publicly available information and our knowledge of technological trends."

The iPhone 5S production, for instance, has hit a snag in trying to incorporate fingerprint sensor to the handset's Home button.

"Apple is the first to attempt this function and technology, and time is needed to find the right coating material, which will likely affect iPhone 5S shipments," the KGI analyst told Apple Insider.

The tech giant is still in the process of solving this puzzle: "How to prevent interference from the black and white coating material under the cover glass."

In the same note, Mr Kuo echoed earlier reports that deploying Retina display screen with the iPad Mini 2 could prove a technical challenge for Apple, making it harder for manufacturers to produce the second-gen small tablet in time.

Bumping up the Mini 2's screen resolution will certainly require more time, which would pushback its rollout to Q4 2013 and dispelling earlier rumours that the compact tablet would arrive anytime between April and August.

Another production concern for Apple involves the budget iPhone, the slimmer casing of which "may make it more difficult to ramp up production yields of coating and surface treatment, and could slow down the shipment timetable," Mr Kuo said.

Lastly, Apple wants to make sure that all the new features that its upcoming gadgets will work well with the new iOS 7, thus requiring more time for software development and testing.

The delays, however, will ensure that the software glitches seen with the iPhone 5 launch last year will not be repeated.