Apple fans fear that the company will face shortage in the supply of iPhones 6 and iPhone 6 Plus units, which could cause the delay in the shipment of the devices to waiting consumers.

Tech giant Apple introduced the new iPhone 6 and iPhone 6 Plus at its launching event last week, and the Apple Store, carriers, and retailers started accepting pre-orders for the devices last Friday, Sept. 12. The units are supposed to hit physical stores this Friday where Apple fans can pick them up. Long queues are expected to form before the opening.

According to sources, at least 80 percent of pre-orders are expected to be delivered on Friday.  However, there are rumors that a shortage is in view due to the unprecedented pre-orders for the two handsets. 

US carrier Verizon Wireless is already facing a delay as much as a month. The 16GB iPhone 6 in space gray and gold variants have a delivery date of Oct. 14, which is a months later than the Sept. 19 launch, while the 64GB and 128GB models will arrive on Oct. 7. AT&T is likewise reportedly facing shipping problems with the iPhone 6 Plus, which has a ship date from 14 to 21 business days.

This is not an isolated problem as supply problems are happening around the globe. In the UK, all 128GB, 64GB and 16GB iPhone 6 Plus models have shipment dates three to four weeks out. In Australia, 16GB iPhone 6 Plus (space gray) units will ship in seven to 10 days, while the 64GB version will arrive in three to four weeks.

Apple has a history of shortage supply with its smartphones. Last year, Apple released two smartphones – iPhone 5S and iPhone 5C. The company did not list the iPhone 5S for pre-order due to supply woes -- customers found it tough to find an iPhone 5S after it went on sale, and some had to wait a month to get a new handset.