iPhone 5 has emerged as the fastest-selling device Apple has ever released with more than two million first-day orders, twice the one million orders iPhone 4S racked up on its launch last October.

"iPhone 5 pre-orders have shattered the previous record held by iPhone 4S and the customer response to iPhone 5 has been phenomenal," Philip Schiller, chief marketing executive of the Cupertino, California, based tech giant announced Monday.

"iPhone 5 is the best iPhone yet, the most beautiful product we've ever made, and we hope customers love it as much as we do," he said.

AT&T, one of the major iPhone carriers had earlier reported that it took a record number of pre-orders both on Friday, the first day they were available, and over the weekend.

Some sceptics had suggested that the reason Apple experienced iPhone 5 stock-outs an hour after pre-orders started was that it had stockpiled smaller supplies of the device than previous models. Apple's and AT&T's announcements would seem to discredit that theory.

Demand for iPhone 5 exceeds the initial supply and while the majority of pre-orders will be delivered to customers in the US Sep 21, many are scheduled to be delivered in October, Apple said.

Come Friday, once again long lines of enthusiastic Apple fans are expected to form in front of Apple stores around the US with many camping out overnight.

And some who want to make a quick buck would offer their line-standing services on Craigslist, making as much as a few hundred dollars holding the spot for someone else.

iPhone 5 will roll out worldwide to 22 more countries Sep 28, including Austria, Belgium, Czech Republic, Denmark, Estonia, Finland, Hungary, Ireland, Italy, Liechtenstein, Lithuania, Luxembourg, Netherlands, New Zealand, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden and Switzerland.