Jason Cipriani/ZDNet

Apple says that its initial supplies of the iPhone 7 Plus have sold out across the world and won't be available in stores when the smaller version of the iPhone 7 hits shelves on Friday.

All variants of the larger model will be impossible to buy in Apple's stores at its Friday retail launch, and Apple suggests it will be difficult for customers to purchase any model if they haven't reserved their purchase ahead of time.

It appears more iPhone 7 models will be available at launch, however the iPhone 7 in the new glossy jet black option sold out during the pre-order phase and also won't be available in stores on Friday, Apple said.

Apple said there will "limited quantities" of the iPhone 7 in silver, gold, rose gold, and black at retail stores.

Customers can however still order all models of the new iPhone via its website, Apple said. Fans may have better luck at Apple's partner retail stores.

"We couldn't be happier with the initial response to iPhone 7 and iPhone 7 Plus, and we are looking forward to beginning sales through our retail stores and partners around the world," Apple said in a full statement posted by TechCrunch.

"We sincerely appreciate our customers' patience as we work hard to get the new iPhone into the hands of everyone who wants one as quickly as possible."

Earlier this week several US carriers reported record pre-order sales for the latest iPhone models with T-Mobile proclaiming the iPhone 7 was the biggest pre-order in its history, up by 400 percent on previous records.

Sprint said initial iPhone 7 and iPhone 7 Plus pre-sales were up 375 percent compared to last year's iPhone 6s and iPhone 6s Plus launch.

Apple this year skipped its usual release of first weekend sales for the latest iPhone because it was no longer a relevant measure of the device's strength with consumers. Apple said initial sales will be "governed by supply, not demand".

The iPhone 7 and iPhone 7 Plus look almost identical to the two previous generation models, except for the missing headphone jack. Both of this years models have upgraded processors, water and dust resistance, and a new home button.

The new iPhones ship with iOS 10, which Apple released for existing iPhones this week, bringing new lock screen notifications, a more visual Messages with iMessages apps, a refreshed Photos apps, and a muted the passcode unlock in favour of Touch ID.

According to third-party figures, iOS 10 adoption reached about 15 percent within the first day, making it faster than iOS 9 adoption.

The new iPhones were to be available on Friday in Australia, Austria, Belgium, Canada, China, Denmark, Finland, France, Germany, Hong Kong, Ireland, Italy, Japan, Luxembourg, Mexico, Netherlands, New Zealand, Norway, Portugal, Puerto Rico, Singapore, Spain, Sweden, Switzerland, Taiwan, UAE, the UK, US Virgin Islands, and the US.

More on the iPhone 7