The ramped up iPhone 6 release date rumors have directly affected iPhone 5S sales.

According to MacRumors, the sales of the current Apple flagship phone plummeted in China as reports emerged a larger iPhone was on its way. But Cantor Fitzgerald Analyst Brian White said Asian buyers will most likely to come back around at iPhone 6 release date.

"In the near term, we sensed disappointment around demand for the iPhone 5S. That said, we heard great enthusiasm around the potential for Apple to introduce a larger iPhone form factor in China this year with the iPhone 6. In our view, the iPhone 6 with a larger screen (e.g., 4.7-inch, 5.5-inch) has the potential to meaningfully accelerate Apple's growth trajectory in China during 2H:14. We have not heard this type of excitement in China around the iPhone in at least two years and thus we believe this could be a very special iPhone launch for Apple," White said.

Another reason of the declined sales of iPhone 5S was the availability of iPhone 5 handsets after it was released by two of China Mobile's larger competitors several months ago.

Other carriers also offered discounted iPhone 5 prices to compete with China Mobile. China is one of the biggest markets of Apple's iPhone. It is also one of the main targets of Apple.

Apple was still tight-lipped when it came to the official specs and features of the upcoming iPhone 6. But it was long rumoured the company will release a larger smartphone to enter the phablet category.

Early reports cited iPhone 6 will come in two variants - one with 4.7 inches screen panel and the other with 5.5 inches display. Other rumored features of Apple handset were a faster A8 processor, iOS 8 and touchID fingerprint sensor.

Regarding iPhone 6 release date, the Cupertino-based tech giant has not announced the official launch of iPhone 6 yet. Speculations claimed the device will roll out in June at the Worldwide Developers' Conference alongside a new operating system.

Other reports claimed the handset will arrive either in September or October.