The report comes as Apple struggles with declining sales of its 10-inch and 7.9-inch tablets, which are faltering as people replace iPads less frequently than expected and larger smartphones made by Samsung Electronics Co Ltd (005930.KS) and other rivals encroach upon sales.
Apple has been working with its suppliers for over a year on larger touch-screen devices, Bloomberg cited the sources as saying.
It is expected to introduce larger versions of its 4-inch iPhone next month, although the company has not publicized plans for its most important device.
Apple was not immediately available for comment-Reuters
