The suppliers of Apple have already started manufacturing the newest model of the iPad tablet, according to sources that have knowledge of the matter.

Mass production for an iPad with a screen measuring 9.7 inches is ongoing. Two of the sources added that the unveiling of the device is expected at either the end of the current quarter or at the start of the next quarter.

The sources added that a new iPad mini, featuring a screen measuring 7.9 inches, will be starting production and will likely begin selling to the market by the end of 2014.

Apple's production plan, including those for its iPad devices, is part of a product push that is crucial to the success of the company over the holiday shopping season at the end of the year. On top of the new iPads, Apple is expected to release the iPhone 6, which will feature bigger screen, and the rumored iWatch, which will be a health-focused smartwatch.

The new iPhones will be unveiled by Apple at a Sept. 9 event. They are rumored to come in two sizes, with one model featuring a 4.7-inch screen and the other model featuring a 5.5-inch screen. Apple's decision to make iPhones of different sizes may have been spurred by the ongoing trend of consumers preferring devices with larger screens.

Last month, Apple CEO Tim Cook said that the company had an "incredible pipeline" that "we can't wait to show you."

Apple is hoping that the new iPad will bring back life to the tablet's sales, which have decreased for the past two quarters. The iPad division of the company is its second-biggest product line after the iPhone, but sales for the tablet have dropped to 13.3 million units for Apple's recently concluded third quarter of its fiscal year. The figure is 8 percent lower compared to iPad sales in the corresponding quarter of last year.

"The one weak spot for Apple has been the tablet market," said RBC Capital Markets Analyst Amit Daryanani, who added that "a refresh could stabilize the iPad's revenue and profitability contribution to the company."

However, despite the sales decline, Cook is still optimistic that the sales of iPad will soon receive a boost due to Apple's recently formed partnership with IBM.

Apple revealed that it only had a market penetration rate of 20 percent for tablet computers used within enterprises, compared to a rate of 76 percent for commercial tablets. The company is hoping that its partnership with IBM, which will create new platforms and dedicated iPhone and iPad apps for businesses, will significantly increase the iPad's market penetration rate in businesses.