The scheme forms part of the most extensive global expansion for the service since the 1940s and has dedicated journalists in Seoul, Washington and London on its payroll.
BBC World Service said in a statement: “Audiences in the Korean peninsula and Korean speakers around the world can now hear radio broadcasts and access the latest news online.”
But on the same day of its launch it was already being jammed by North Korea on its short and medium wave frequency, experts in South Korea are reporting.
Any residents of the prison state who were able to listen to the taxpayer-funded bulletins would be risking severe punishment from the authorities.
The multi-million pound Government grant is being used to fund 12 new BBC operations including services in the languages Pidgin, Punjabi and Yoruba.

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The Korean language programmes will broadcast for three hours a day on shortwave and one hour on medium wave.
Francesca Unsworth, director of the World Service: “BBC News Korean will build on the long-standing reputation for fairness and impartiality the BBC World Service has earned all over the world.”
A BBC World Service spokesman revealed that the signal was mostly getting through to North Korea according to their own monitoring, despite efforts by Kim Jong-un’s lackeys.
The move to block BBC News Korean came as tensions reached their most volatile yet with North Korea outing a determination to annihilate the US.
North Korea said: “It is the stern determination and will of the DPRK to annihilate the US imperialists, the ringleader of aggression, to the last man on this planet.”
Donald Trump warned that the military response to North Korea’s aggression would be “devastating” after Pyongyang moved military assets including warplanes to the east coast.