Developers noted evidence that the OS likely to appear with Apple’s next iPhone, iOS6, is already being tested by the company, pointing to a June release at the company’s World Wide Developers Conference. The reports coincide with speculation that the next version of the smartphone will have a larger screen.

9to5Mac reports that references to the iOS6 beta have been found in the code strings on the iCloud.com online storage beta site, suggesting that Apple is already carrying out compatibility testing. App developers have also noticed in their analytics that a handful of app users have been running iOS6 in the past week – other developers said they have been seeing similar hits since the end of April.

Rumoured features of the next version of iOS include Apple’s new Maps app and 3D capability.

According to Reuters, the next iPhone will also feature a larger screen, with claims that Apple has already placed orders for the displays with suppliers in South Korea and Japan. It will reportedly be 4 inches compared to the current 3.5 inches, a 30 percent increase.

The recently-announced Samsung Galaxy S3 – the iPhone’s main rival – features a 4.8-inch screen.