The Apple iPad 3 will support super-fast 4G wireless technology and a high-resolution retina display when it goes on sale in March, according to supply chain sources.

Bloomberg reported that three employees at the Foxconn factory in China where iPhone and iPads are produced told it that the iPad 3 will get 4G (also known as LTE) technology before the iPhone.

"Apple's next iPad, expected to go on sale in March, will sport a high-definition screen, run a faster processor and work with next-generation wireless networks," Bloomberg said.

The agency said that widespread speculation that the iPad will feature a high-resolution retina display, as seen on the iPhone 4S, had been confirmed. The iPad would have "more pixels on its screen than some high-definition televisions". "The pixels are small enough to make the images look like printed material," a source said.

Bloomberg's sources believe that the iPad 3 will have a quad-core processor, boosting computing power significantly over the dual-core iPad 2, meaning faster multitasking and scope for developers to create even more detailed and realistic games.

The introduction of 4G would make the iPad 3 the first Apple product and the first tablet on the market to support the technology, but 4G will not be available in the UK until at least the end of 2012.

Mobile operator O2 is trialling its 4G service in some areas of London but only for about 1,000 customers and businesses. With the lack of 4G in the UK and other countries, Apple might produce two versions of the iPad 3 - one with 4G and one without - as is the case with some smartphones.

With regard to design, it is commonly believed that the iPad 3 will closely resemble the iPad 2, although it may be slightly thicker to accommodate the new screen.

"Mass production began at the start of this month [January], with factories running 24 hours a day in China," said Bloomberg. Manufacturing will halt over China's Lunar New Year holiday ramp back up to a peak in February."

Apple has not made an official comment on the iPad and will not comment on rumour or speculation but a media launch event is expected soon.