Apple preparing 12.9-inch iPad for March 2015 launch

New 9.7-inch and 7.9-inch screens will be ready by Christmas - with a 13-incher out next year

Apple's suppliers are working hard to manufacture the company's largest-ever iPad - stretching the screen size diagonally from 9.7 inches to 12.9 inches.

Production for the new iPad, people with knowledge of the matter told Bloomberg, is scheduled to begin by the first quarter of 2015. That would imply a launch already being prepared for the new iPad in March 2015.

The Cupertino, California-based company currently produces the iPad Mini with a 7.9-inch screen and the main iPad, which comes with a 9.7-inch screen.

According to Bloomberg's sources, the company has been working with suppliers for at least a year to develop a new range of larger touch-screen devices, fleshing out its line-up in order to attract a wider range of customers.

The news comes as sales of the iconic iPad device have declined for the past two quarters. Apple's CEO, Tim Cook, may be keen to tinker with the iPad range and there have been many reports that Apple is looking to make big changes to its iPhone line-up too, with bigger screens for its smartphones as well.

People familiar with Apple's plans said that the company will also launch a new version of the 9.7-inch iPad and the iPad Mini, with both set to launch in volume before Christmas this year.