Apple will open its second research and development centre in China in the southern city of Shenzhen, the US technology giant said Wednesday, as it seeks to improve sales in the crucial market.

California-based Apple announced in August a similar facility would be built in Beijing.

Situated close to the border with Hong Kong "Shenzhen is an incredibly dynamic city... we are impatient to open a new research and development centre next year", Apple said in a statement sent to AFP.

Apple has seen its market share eroded in China's booming smartphone market this year, beaten out by rising Chinese firms -- market leader Huawei and three companies little known elsewhere, Vivo, Oppo and Xiaomi.

Apple has also struggled with the country's Communist authorities, despite regular visits from chief executive Tim Cook.

Apple's iTunes Movies and iBooks services were launched in China last year, but were then promptly blocked by Beijing.