A South Korean venture firm said Monday it has filed a complaint with the prosecution against Apple Inc.'s Seoul-based branch for patent infringement on messenger service technology.

Infozone, a mobile message solution provider, claimed that Apple's iMessage service, installed on iPhones since June 2011, infringed its patent for the technology of switches between different data-transmission networks depending on the condition of receivers' handsets.

"If an iPhone user sends messages through iMessage to another iOS-powered user, the service will be free, like KakaoTalk.

However, when the receiver is using another operating system via Samsung or LG handsets, iMessage will use paid mobile networks," said Park Myung-heum, who heads Infozone. "This is where Apple infringed our patent."

"The lawsuit will cover all Apple devices, including those that run on the latest iOS8 operating system," Park added. "This is also to prevent other tech giants or global players from depriving local small- and medium-size firms."

"We are now consulting with a lawyer concerning the issue and have not yet determined details, including the amount of compensation to be requested," Park said. The company will also seek a sales suspension of Apple products, he said.

An official at a local public relations firm representing Apple Korea said the company has no statement on the issue.

Apple Inc. is the subject of a handful of lawsuits around the globe, including an ongoing court battle with Samsung Electronics Co. on its home turf since 2011. The two companies agreed in August to drop all disputes outside the U.S. (Yonhap)