TOKYO - Apple Inc plans to use a larger screen on the next-generation iPhone and has begun to place orders for the new displays from suppliers in South Korea and Japan, people familiar with the situation said on Wednesday.

The new iPhone screens will measure 4 inches from corner to corner, one source said. That would represent a roughly 30 per cent increase in viewing area, assuming Apple keeps other dimensions proportional.

Apple has used a 3.5-inch screen since introducing the iPhone in 2007.

Early production of the new screens has begun at three suppliers: Korea's LG Display Co Ltd, Sharp Corp and Japan Display Inc, a Japanese government-brokered merger combining the screen production of three companies.

It is likely all three of the screen suppliers will get production orders from Apple, which could begin as soon as June.

That would allow the new iPhone to go into production as soon as August, if the company follows its own precedent in moving from orders for prototypes for key components to launch.

Apple's decision to equip the next iPhone with a larger screen represents part of a competitive response to Samsung Electronics Co Ltd.

Samsung unveiled its top-of-the line Galaxy smartphone with a 4.8-inch touch-screen and a faster processor earlier this month.

With consumers becoming more and more comfortable using smartphones for tasks they once performed on laptops, like watching video, other smartphone manufacturers have also moved toward bigger displays.