Many Apple iPhone 4 owners have found yellow spots marring the display of the new device.
This is not the first time display issues have cropped up with a new Apple product - earlier this year, users complained that the screens of their new 27in iMac computers had a yellowish tint.
Apple had acknowledged the fault in February and offered refunds.
A number of blogs including Gizmodo and MacRumours have reported that complaints have been pouring in from all parts of the world about yellow spots and lines on the new handset's high-resolution Retina Display screen. Gizmodo said it had already received 27 reports of the problem.
Other users reported problems receiving signals with the new device, claiming that reception decreases significantly when the new iPhone is held by its sides, affecting both calls and downloads.
Apple representatives are yet to comment fully on the issues, but have advised customers experiencing these problems to visit the Genius Bar tech support centre at their nearest Apple store.