Apple said Wednesday that the white version, which had been scheduled to go on sale on Thursday, will be delayed until next month because of manufacturing difficulties. "White models of Apple's new iPhone 4 have proven more challenging to manufacture than expected, and as a result they will not be available until the second half of July. The availability of the more popular iPhone 4 black models is not affected," Apple said in a brief statement.

White and black model iPhones had been scheduled to go on sale in stores in Britain, France, Germany, Japan and the United States on Thursday and Apple fans are already queuing up to buy the latest generation of the popular device.

Apple and its wireless carrier AT&T were also forced to suspend pre-ordering of the iPhone 4 last week amid heavy demand. Apple said it had received a single-day record 600,000 orders for the new iPhone.

The delivery delay for the white iPhone 4 comes two months after Apple was forced to put back the international release of its new touchscreen tablet computer, the iPad.

Citing demand in the United States that was "far higher than we predicted," Apple in April delayed the release of the iPad outside the United States for a month.