The new iPhones of Apple will be experiencing shipping delays as the massive demand for the smartphones greatly outweigh Apple's supply of the devices.

According to Apple's website, customers who pre-order for the iPhone 6 Plus will have to wait three to four weeks for the device to arrive. Customers who pre-ordered for some models of the iPhone 6, on the other hand, will have to wait seven to 10 business days for the device. Certain versions for the iPhone 6, however, are still ready for delivery by Sept. 19, when the new Apple smartphones are scheduled to be released to stores.

Pre-orders that customers make through other carriers, however, might take much longer.

"Response to iPhone 6 and iPhone 6 Plus has been incredible, with a record number of pre-orders overnight," said Apple spokeswoman Trudy Muller.

The 4.7-inch iPhone 6 and the 5.5-inch iPhone 6 Plus were unveiled by Apple in a highly publicized media event last Sept. 9, after months of rumors and speculations regarding the smartphones. Other products that Apple introduced in the event include the Apple Watch, the company's first entry in the wearable technology market, and the Apple Pay service, which looks to be the substitute for users in using credit cards to pay for purchases.

The iPhone 6 costs from $199 to $399 on a two-year contract, and the iPhone 6 Plus costs $299 to $499 on a similar two-year contract. The devices come in gold, silver and space gray.

At a media conference, AT&T mobile division CEO Ralph de la Vega said that the massive demand for the new iPhone is the most that the company has seen for the past couple of years.

This massive demand will be causing shipment delays for the device, which is something that is not new to Apple when it released a new iPhone.

When the iPhone 5 was released in 2012, shipments for the device were delayed by a week. Back in 2011, the then newly released iPhone 4S was sold out in top carriers AT&T, Verizon and Sprint just after five days from the start of the pre-order period.

This time, both iPhones are experiencing supply problems, with the supply of the iPhone 6 Plus more severe than that of the iPhone 6.

To further worsen the imbalance of supply and demand, carriers are offering deals to lure customers to purchasing an iPhone 6 from them.

Verizon has a Trade In & Trade Up promo that offers between $100 to $300 for used smartphones. AT&T said that customers may trade in their old iPhone for an iPhone 6 and up to $300 credit. Sprint has the iPhone for Life promo, which allows customers to rent the iPhone 6 for $70 monthly to be able to upgrade to a new version after every two years. T-Mobile, on the other hand, said that it will give a better offer on any trade-in price by $50.

The new iPhones will be available in 150 countries by the end of 2014.

The handsets will initially be available in a limited set of markets -- including the U.S., Australia, Canada, France, Germany, Hong Kong, Japan, Puerto Rico, Singapore and the UK -- for pre-order today and shipping on Sept. 19, the company said. China, one of Apple's biggest markets, won't get the new devices at first, though the company said it plans to have the devices in 150 countries by the end of the year.