Canadian pastor Hyeon Soo Lim's life sentence to hard labour in North Korea is "outrageously unjust", according to a friend who knew him while he worked in the totalitarian state.

The friend, a defector from North Korea, told Daily NK that the harsh sentence passed on the pastor, born in South Korea, was egregrious, especially given how much voluntary work he had done for the people of North Korea.

North Korea's highest court last month sentenced Pastor Lim to hard labor for life for subversion. He had been held by the country since last February and appeared on North Korean state media confessing to crimes against the state.

The source, who requested anonymity, said he knew the pastor in Canada and would go on trips with him, attend his sermons and support his work.

"He really helped people like me who are from North Korea a lot. In some ways, I would say a lot of people from the North managed to get permanent residency in Canada thanks to his help. He provided a lot of financial help but also supported us so we would be able to settle down quickly in Canada. Defectors who were able to get permanent residency thanks to Pastor Lim now have stable lives in Canada."

He said Pastor Lim had lived in the same apartment for 25 years and had an old Korean car. "In North America, if you have a church with over 3,000 members in the congregation, it's considered a huge church. I don't know how this will sound, but had he wanted to, he would have been able to live a comfortable life in Canada, but he didn't choose to live that way at all."

Pastor Lim visited North Korea regularly. 

"He would go to the North two to three times a month. All combined, I think he has visited more than 100 times," the source added. His activities there included building a bread factory in the Rajin-Sonbong area and a service to help North Korea's homeless children who often beg for food. He also built a noodle factory and sent aid from Canada.

People were shocked when Lim was detained, the source said. "He went there not for any political reasons but because he wanted to help the North Korean people."

They feared the worst when he did not return home. "North Korea easily can hold someone captive or kill them if they think that person doesn't suit their taste. That had become reality."