North Korea says it has sentenced a South Korean Christian missionary to hard labour for life after convicting him of attempting to set up underground churches and of espionage.

The country's official KCNA news agency reported that the man, who was arrested last October after crossing into the country from China, had admitted his guilt at a court trial on Friday.

The rival Koreas have different English spelling styles for Korean names, so the North called the missionary Kim Jong-uk, but Seoul has previously referred to him as Kim Jung-wook.

Kim was put on show at a televised event in February when he confessed to spying for the the South Korean intelligence agency as well as to his church activities.

"The accused admitted to all his crimes. He tried to infiltrate into Pyongyang after illegally trespassing on the border for the purpose of setting up underground church and gathering information about the internal affairs of the DPRK [North Korea] while luring its inhabitants into south Korea and spying on the DPRK," KCNA said.

South Korea has denied any spy links to Kim. In the past, North Korean authorities have staged news conferences where detainees are presented before the media to make statements that they later recant.

Strict religious laws

Christian missionaries have been drawn over the years to North Korea, which only tolerates sanctioned religious services.

North Korean defectors have said that the distribution of Bibles and secret prayer services can mean banishment to a labour camp or execution.

Outside analysts have said that North Korea has previously used foreign detainees as bargaining chips in efforts to receive outside aid and political concessions. The sentencing comes amid rising tensions on the Korean Peninsula, which is still technically in a state of war because the 1950-53 Korean War ended in an armistice, not a peace treaty.

North Korea is still holding Kenneth Bae, a Korean-American missionary sentenced to 15 years of hard labour on charges of trying to use religion to overthrow its political system.

The isolated country has twice cancelled visits by Robert King, the US special envoy for North Korean human rights issues, to discuss Bae's case.

Earlier this year, an Australian, John Short, was arrested in Pyongyang for allegedly trying to distribute Christian materials. He was later released after he apologised.