Camps and detention for top leaders part of plan as Kim Jong Un's last big backer takes dim view of his future.
China has drawn up detailed contingency plans for the collapse of the North Korean Government, suggesting it has little faith in the future of Kim Jong Un's regime.
Documents drawn up by planners from China's People's Liberation Army and leaked to Japanese media include proposals for detaining North Korean leaders and setting up refugee camps on the Chinese side of the frontier in the event of an outbreak of civil unrest in the secretive state.
The report calls for increased monitoring of China's 1415km border with North Korea.
It says any senior North Korean military or political leaders who could be the target of rival factions or another "military power" - thought to be a reference to the United States - should be given protection.
According to Kyodo News, the Chinese report says senior North Korean leaders should be detained in camps where they can be monitored and prevented from directing further military operations or taking part in actions that could be damaging to China's interests.
The report suggests "foreign forces" could be involved in an incident that leads to the collapse of internal controls in North Korea, resulting in millions of refugees trying to flee. The only route to safety for most would be into China.
Chinese authorities intend to question new arrivals, determine their identities and turn away any considered dangerous or undesirable.
"This only underlines that all the countries with a stake in the stability of northeast Asia need to be talking to each other," a visiting scholar at the Meiji Institute for Global Affairs, Jun Okumura, told the Daily Telegraph.
"What we have learned from the collapse of other dictatorships - the Soviet Union, Muammar Gaddafi's Libya - is that the more totalitarian the regime, the harder and faster it falls.
"This is why we need contingency plans, and I am sure the US and South Korea have extensive plans, but the release of Chinese measures is new.
Okumura believed the timing of the leak of the study was significant, as China could have been expected to have had similar plans for the past 20 years as North Korea teetered on the edge of implosion.
The release of the study comes days after Beijing issued a thinly veiled warning to Pyongyang, before an expected nuclear test, that China would "by no means allow war or chaos to occur on our doorstep".
China, North Korea's sole remaining significant supporter, also refused to export any crude oil to it in the first three months of the year.