Taiwanese smartphone manufacturer HTC is planning its own Windows RT tablets according to Bloomberg.

The company plans both a 7-inch and a 12-inch device which can also make phone calls, the news wire reports a person familiar with the company as saying.

"HTC's products, to debut in 2013, will be based on the Windows RT version of Microsoft's operating system, designed for machines with chips using technology from ARM Holdings, according to a person familiar with the plans," said Bloomberg, "Delays in those machines, as well as another version running on Intel's chips, have meant Microsoft has few Windows devices capable of challenging Apple's iPad."

Microsoft released its flagship Surface tablet in October based on its new Windows RT operating system, alongside its new Windows 8 desktop OS and Windows Phone 8 OS for smartphones. Its revamped operating systems were designed to help integrate the Windows experience across a range of touchscreen devices and traditional PCs and help the company gain ground on Apple and Google in this area.

However, the company has struggled to sell as many of the new Windows RT machines as projected, and was forced to cut production of its own Surface tablets from four million units to two million, according to Taiwanese site DigiTimes.

Microsoft's partners which also make Windows RT-based touchscreen devices, such as Dell and Asus, are also said to be struggling with sales, and the company is now in a rush to get the devices out to more retailers.

HTC's Windows RT tablets are scheduled to be released in Q3 2013, according to Bloomberg, with the devices expected to run on chips from Qualcomm. HTC is one of Microsoft's most important partners in smartphones, being one of only two companies so far to release a Windows Phone 8 handset. The other is Nokia which recently released its Lumia 920 and Lumia 820 based on the new operating system. With their close relationship with Microsoft in the field of smartphones, HTC and Nokia are natural partners when it comes to expanding their range to include tablets.

However, Nokia is yet to give a sign that it's gearing up to produce its own Windows RT offering. But, DigiTimes is reporting that the Finnish company is discussing development of a 10-inch Windows RT tablet, and is likely to unveil the model at the 2013 Mobile World Congress in Barcelona, Spain, during February 25-28, according to Taiwan-based supply chain makers.

"Nokia originally planned to develop a 10-inch Windows RT tablet equipped with Qualcomm's S4 processor in first-quarter 2012, with Compal to undertake ODM production and initial shipments of 200,000 units to test the market," sources told DigiTimes. "But because Microsoft later announced Surface, and the market for Windows 8/RT tablets needed to be proven, Nokia internally focused on smartphones, and delayed the development of the 10-inch Windows RT tablet, the sources pointed out."

DigiTimes says that Nokia is evaluating order volumes and has not yet decided on its marketing plans for a Windows RT device.