Apple could unveil a fifth edition of its blockbuster iPhone at an event scheduled in San Francisco next week.

The Cupertino, California-based technology giant sent out invites on Wednesday to media outlets for a product announcement on September 12.

The invite provided a subtle hint to the possibility that the company could launch the iPhone 5 at the event.

A brief message on the invite reads 'It's almost here' and has a large number 12 that casts a shadow of the numeric five, hinting that the product to be unveiled will be the fifth edition of the iPhone.

The Tim Cook-led firm's

anticipated launch of the new version of the iPhone comes as several major technology companies are lining up to launch new products.

Nokia and Motorola Mobility are also likely to unveil new smartphones.

The Wall Street Journal said the new iPhone is expected to have a slightly larger screen but would look similar to the current model i Phone 4S, which was launched last year.

It would run the latest version of Apple's mobile software and features a new mapping application.

The company sold 26 million iPhones in third quarter ended June 30, representing a 28 per cent growth over the year-ago quarter.

Apple sold 17 million iPads during the quarter, up 84 per cent from the year-ago period.