Demand for Apple's flagship iPhone 6 and iPhone 6 Plus remains extremely strong, even as the product cycle begins to wind down, while consumer interest in the Apple Watch is outperforming the first iPhone, new data reveals.

Morgan Stanley on Wednesday published the findings of its latest AlphaWise Trackers, the results of which were shared with AppleInsider. Analyst Katy Huberty revealed that the data shows demand for the iPhone is estimated at about 53 million units for the June quarter, with particularly strong interest coming from China.

Corroborating these figures are supplier estimates in Asia, which peg Apple to build about 54 million iPhones in the quarter. Huberty believes Apple is looking to add some channel inventory with excess units, as the company exited the March quarter at the low end of their 5-to-7-week range.

As for the Apple Watch, Morgan Stanley's data has found that demand for the wrist-worn device is stabilizing at a level 20 percent higher than the first-generation iPhone six weeks after launch. The AlphaWise survey compiles sell-through data using Web search analysis.