Apple's next move: Rumours suggest iPhone 6 will be a 6in phablet to rival Samsung's Galaxy Note 3

Following the impending release of the iPhone 5S and iPhone 5C, it looks like Apple may be set to further diversify its smartphone offerings with a phablet-style device potentially dubbed the iPhone 6.

The tech firm is currently testing screens ranging from 4.8in up to 6in, sources working for Apple's component suppliers have told The Wall Street Journal.

The iPhone 5 has a 4in screen, so it is likely that any device using a 6in screen would be marketed as a separate class of smartphone and a competitor to the likes of the Galaxy Note 3, which Samsung recently launched at IFA 2013

It is possible, however, that the company could choose to develop the iPhone 6 - expected next year - with a larger screen and the WSJ's mystery informants said that the firm seems most interested in a 4.8in form factor.

When the iPhone was initially released, the company made much of the fact that it had created a single, all-encompassing device. However, it is the lack of diversification that has partly led to the firm losing ground to Samsung.

The new products may be particularly aimed at China - the biggest smartphone market in the world - where the firm currently holds less than five per cent market share, compared to Samsung's 17.6 per cent hold on consumers.

Although it is an Apple strategy to only offer a small choice of products at any given time, the iPhone is currently the sole device group which does not have different tiers based on price and functionality - the firm currently offers two sizes of iPad, a range of iPods and two classes of MacBook.

If you've got your watch set to count down mode ahead of Apple's big 10 September unveiling, then follow our live updating coverage of the iPhone 5S and iPhone 5C launch for all the latest news and analysis and be sure to join us on the day.