Apple's iPhone 6 Plus, which has a 5.5-inch display, goes on sale in U.S. stores on Sept. 19.
Websites of Apple's carrier partners, Verizon Wireless, AT&T and Sprint also showed delays of up to six weeks.
In adition, Apple's website crashed for a while on Friday, possibly due to heavy traffic.
The iPhone 6 costs $199 to $399 with a two-year contract, while the 6 Plus is priced at $299 to $499.
The handsets will initially be available in the U.S., Australia, Canada, France, Germany, Hong Kong, Japan, Puerto Rico, Singapore and the U.K. 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.
The likely delayed launch of the new iPhone 6 in China sparked a race to pre-order the phone in Hong Kong on Friday. Pre-orders for the iPhone 6 and iPhone 6 Plus sold out within two hours on Apple's Hong Kong website. As you realize, many of those devices will be smuggled across the border into mainland China.