Microsoft has announced that it will miss its target of launching its Windows Phone 7 handsets in China, stating that the devices will be available in the country in the first half of 2012, rather than by the end of 2011, as originally planned.

The firm said that it is working to “ensure local citizens have a great experience with Windows Phones”, adding that it is working with partners in China to assess the best timings and channels for the devices to go to market in the country.

China is a key market for Microsoft, as penetration of its Windows smartphones in the country is expected to grow more than 20-fold over the next five years, from just 0.87m devices on the market today, to 18.92m units by the end of 2016, according to forecasts from Informa Telecoms & Media.

The company had has been in discussions with Chinese handset makers including Lenovo, ZTE and Huawei Technologies about developing Windows Phone 7 devices for Chinese consumers, and it is not currently clear which handset manufacturer will launch the first handsets on the OS in China.

At the launch of Nokia’s Lumia Windows Phone 7 handsets in October this year, Nokia CEO Stephen Elop said the firm would launch the  introduce the two Lumia devices in Hong-Kong and Taiwan before the end of 2011, but would only follow with a portfolio of products in mainland China in the first half of 2012.

Meanwhile, Lenovo’s LePhone product manager Yue Chen recently stated that there is a clear schedule for the firm’s own Windows Phone devices, but it would not be until late next year.

“We are indeed currently considering a Windows Phone-based LePhone product, and we already have a clear release schedule — it will be released during the second half of 2012,” said Chen.