The Apple logo.
IN PHOTO: The Apple logo is pictured at a retail store in the Marina neighborhood in San Francisco, California April 23, 2014. REUTERS / Robert Galbraith

In spite of assurances from Apple, the likelihood of serious stock outs immediately after the iPhone 6 release date on September 19 appears to be increasing.

As of September 12 or Friday last week, the tech giant has attracted around four million iPhone 6 pre-orders that combine the reservations made for the 4.7-inch model and the 5.5-inch iPhone 6 Plus.

It is expected that millions more will rush to Apple Stores and other retail outlets where the device will sell Friday this week, further convincing Apple watchers that the 2014 iPhones will shatter all existing records.

But will the iPhone maker's inventory sufficient enough to meet the increasingly heavy demand for the next iPhone?

With the way things are going, it could be mad scramble starting this Friday and in the days, weeks and months ahead as there are three signs the ongoing mass production of the iPhone 6 will fall short of expectation.

Apple overwhelmed

Actually, it is Apple's major manufacturing partner, Foxconn, which has its hands full. According to The Wall Street Journal, the China-based device maker has been producing 540,000 units of the combined iPhone 6 and iPhone 6 Plus (more of the former at 400,000) per day with the manufacturing activity at ramped up mode.

Notwithstanding, a Foxconn employee told the publication that "the volume is still not enough to meet the preorders." Basing on this report, it can be assumed that supplies will be scarce on iPhone 6's actual commercial debut.

Limited iPhone 6 phablet

In the same report, the Foxconn insider claimed too that only 140,000 units of the iPhone 6 Plus are being assembled every day, suggesting that the upsized device will be hard to find starting September 19 and in the immediate days and weeks ahead.

The same source blamed the limited supplies of 5.5-inch display panel for the imminent iPhone 6 Plus supply shortage.

Foxconn work stoppage

Thursday last week, some 3500 Foxconn workers located in Brazil have decided to walk out until their demands for better pay and other work-related conditions are met. According to 9to5Mac, the striking employees appear hell-bent to paralyze Foxconn's assembly lines as they are preventing other workers from entering the production.

It is mentioned in the same report that Foxconn's manufacturing complex in the country is engage in the large-scale production of iPhones and iPads though not in the same gigantic amounts compared to its China-based counterparts.

Still, the ongoing production halt is feared to negatively impact on Apple's post iPhone 6 release date plan of bringing the device to all market destinations possible at the soonest possible time.