Apple's sixth generation of iPhone may have a larger screen than its previous models, U.S. media reported on Wednesday.

Apple is working with several screen makers on the new phone and "the new screens measure at least four inches diagonally," said The Wall Street Journal in a report, citing people familiar with the matter.

Production is set to begin next month and the screen makers Apple is working with South Korea's LG Display, Japan's Sharp and Japan Display, which was created last month by three Japanese companies and the government, according to the report.

The screen of iPhone 4S, Apple's latest iPhone model, measures 3.5 inches from corner to corner. If Apple keeps other dimensions proportional, a four-inch screen will have around 30 percent increase in viewing area.

Since a large selection of smartphones running on Google's Android operating system have larger screens, Apple has been rumored to increase iPhone's screen size in numerous reports in previous years.

If the reports are accurate this time, the next iPhone, which is expected to be introduced this autumn, will be the first iPhone to have a screen larger than 3.5 inches.