Microsoft has made it harder to monitor calls and chats over its Skype phone service on the mainland, said an advocacy group for freedom of expression, as the central government steps up censorship of the internet.

An onslaught of companies offering voice calls and text messaging for free over the internet has forced telecommunications network operators to radically rethink their business models.

Skype, the instant messaging and online voice-and-video-call service owned by Microsoft, will be relaunched in mainland China under a new joint venture, following the end of a long-standing alliance in the market with Tom Group, the Li Ka-shing-controlled media conglomerate.

Park Geun-hye is officially headed to the Blue House as the country's first female president. Park, the daughter of a former strongman, has already faced a test over Pyongyang's recent nuclear missiles testing.