Some users who purchased the iPhone 4 have found yellowish spots and bands marring the device's high-resolution display.
Several blogs, including TUAW and Gizmodo, reported user complaints of yellow discoloration on the phone's screen, which offers significantly higher resolution than screens on previous versions of the handset.
Pictures of the problem posted online by Gizmodo showed faintly yellow patches and bands crossing the screen.
An Apple spokeswoman could not immediately be reached for comment about the reported screen problems.
The iPhone 4 went on sale today, starting in Japan. However, some users in the US who preordered the new handset received their phones before retail sales started.