THE world's best-selling tablet computer received a major overhaul today, becoming the first Apple product to connect to next-generation 4G mobile networks and gaining a high-definition screen, more graphical grunt, voice dictation and a significantly better camera for the same price as the old model.

But Australians will not be able to use the new iPad’s new speedy 4G connection, which is incompatible with the country’s only 4G network, when it arrives in local stores on March 16.

Apple chief executive Tim Cook revealed the third iPad tablet in San Francisco early this morning, in a performance that will be judged as his first real test as head of the company after he took over from founder Steve Jobs.

Mr Cook said the iPad had created a new category with the tablet that Apple would "redefine" again with the new edition iPad.

"We think that iPad is the poster child of the post-PC world,’’ Mr Cook said.

"The momentum behind Apple has been incredible and has surprised almost everyone. We sold 15.4 million in the last quarter alone. We sold more iPads in the fourth quarter of last year than any PC manufacturer sold of their entire PC line worldwide."

The new iPad will be the first Apple product to use a 4G (LTE) mobile internet connection that could deliver a speed boost of up to five times that of current networks.

Unfortunately, it is not yet equipped to work with Australia’s first 4G network, offered by Telstra, as it uses a different frequency (1800MHz) to 4G networks available in the United States.

Other than 4G compatibility, the new iPad’s most obvious upgrade is its 9.7-inch screen, which now features double the resolution (2048x1536) to a high-definition “Retina” display as seen in the iPhone 4.

Apple worldwide marketing vice-president Phil Schiller said the screen upgrade is designed to better show off HD movie downloads, books and photos, with pixels indiscernible to the naked eye, however app makers and iPad users may need to upgrade their software to make full use of the new display.

Apple's new iPad will also feature a more powerful processor - a 1.5GHz dual-core A5X chip with quad-core graphics processing - that will enable the use of more demanding apps, including video-editing software and games.

However, the company stopped short of adding a quad-core computing processor as rumoured and seen in some rival tablets including the ASUS Transformer Prime.

The new iPad also features a significantly better rear camera that now offers a backlit sensor, 5-megapixel resolution and hybrid infra-red filter for better colour reproduction, as well as voice dictation that is designed to recognise the Australian accent.

The new iPad has retained its original US price, starting at $US499.

Apple has sold more than 55 million iPads since its April 2010 launch, dominating the fledgling market.

Despite increased competition from Samsung, Motorola, Sony and ASUS, Gartner predicts Apple will continue to lead the category this year with 69 million tablet sales compared to just 22 million Google Android-run tablets, even though its rivals are closing the hardware gap.

Apple also revealed an upgraded Apple TV set-top box at the event that will support full high-definition movie and TV downloads, up from a current resolution of 720p.

The small black box will also come with a new menu featuring options resembling iPod icons. It will be launched in the US on March 16 for $US99.

Jennifer Dudley-Nicholson travelled to San Francisco as a guest of Apple.

