The head pastor of one of Canada's largest congregations who has been detained by North Korea since February appeared before media in Pyongyang and confessed to crimes aimed at overthrowing the state, the North's official news agency said on Friday.

The KCNA news agency said Hyeon Soo Lim, of the 3,000-member Light Korean Presbyterian Church in Toronto, "honestly admitted to all crimes" he was accused of committing.

KCNA quoted Lim as telling a news conference he had traveled to North Korea in the guise of humanitarian work and gathered information that he used in sermons outside the country in a bid to drive the regime to a collapse "with the love of God".

His purpose was to "overturn its social system by taking advantage of the hostile policy against it sought by the South Korean authorities and set up a base for building a religious state," KCNA quoted him as saying.

Lim also said he worked with South Korean and U.S. authorities to "lure and abduct" North Koreans in a campaign of aiding defectors from the country, KCNA said.

The church said in March that North Korea detained Lim during one of his regular humanitarian missions there.

South Korean-born Lim has visited North Korea more than 100 times since 1997 and has helped establish an orphanage and a nursing home there, according to the church. He has lived in Canada since 1986 and is a Canadian citizen.

Canadian media have reported on Lim's extensive business dealings in North Korea, including ramen and wig factories, gas stations, farms and fishing operations.

Church spokeswoman Lisa Pak said she was aware of the latest North Korean reports. "That's the most that we know, that the press conference happened and he admitted, I use that word very lightly, to some charges," Pak said.

In a statement provided by the church on Thursday, Lim's family said it had no comment regarding the charges and allegations, "except that the humanitarian aid projects that Mr. Lim has both initiated and supported in the DPRK have been for the betterment of the people".

Officials at Canada's Foreign Affairs department are "deeply concerned", a spokeswoman said in a statement. "We continue to advocate for consular access and for a resolution in his case."

Canada suspended diplomatic relations with Pyongyang in 2010. Both North Korea and China have clamped down on Christian groups over the past year, and several American Christians have been detained by North Korea.