Shanghai Zhizhen Network Technology has accused Apple of infringing its patent used in the Siri digital assistant on iPhones and iPads.

Zhizhen Network claims that the iPhone maker infringed its patent for voice recognition software and filed a lawsuit in June 2012, requesting the company to halt production and sales of products with Siri in China.

The Chinese firm said Siri infringed its Xiao i Robot software, which was patented in 2004, and claimed that Apple’s Siri was first developed in 2007.

In 2009, Zhizhen Network obtained a patent license from China’s State Intellectual Property Office and the license is still valid.

Zhizhen’s lawyer Yuan Yang was quoted by Shanghai Daily newspaper as saying that "Apple has unveiled more products with the Siri application after we filed the lawsuit."

"We think all the above products infringed the patent right of ‘Xiao i Robot’" voice recognition software," Yang said.

Apart from Zhizhen Network, Taiwan’s National Cheng Kung University has also filed a lawsuit against Apple in July last year, claiming that Siri infringed on two patents held by one of its research teams, related to speech recognition.