At least 13 refugees from North Korea have been arrested in the south-western Chinese city of Kunming while they were trying to reach South Korea, media reports said Monday.

"It appears that they were trying to save money for hiring brokers who could help them cross the border," said one activist quoted by Yonhap news agency.

"Most North Korean defectors travel in a group of five at most when crossing the Chinese border to a Southeast Asian nation."

One newspaper, Dong-A Ilbo, put the number of arrests at 15.

A spokesman for the South's unification ministry, which handles cross-border affairs, said Seoul was trying to verify the report.

Some 25,000 North Koreans have fled famine or repression at home to settle in the capitalist South over the past six decades.

Almost all cross the North's border into China, before venturing to Southeast Asia where they arrange to fly to South Korea for resettlement.

China, the North's sole major ally, considers the fugitives to be illegal economic migrants instead of refugees and repatriates those whom it catches.

Rights groups strongly criticise Beijing's policy. The fugitives can face severe punishment including a term in a prison camp once they are sent back to the North.

"These people that you have mentioned are not defectors from the DPRK (North Korea)," China's foreign ministry spokesman Qin Gang said.

"They are illegal border crossers. In dealing with relevant issues we have always abided by domestic law, international law and humanitarian spirit."

Asked if he was confirming the detainees were North Koreans, he said: "I'm not aware of the specific issue as well as the specific persons involved in the issue."

The North's young leader Kim Jong-Un is believed to have tightened border controls since he took power in late 2011.

The number of refugees arriving in South Korea plunged more than 40 percent to 1,508 last year.

AFP