China's military preparing for a potential crisis with North Korea

North Korean leader Kim Jong -un. Photo / AP

By Matthew Dunn

China is preparing for a potential crisis with North Korea by strengthening its defences along its 1400 kilometre border with the secretive state.

As part of the decision, which coincides with US President Donald Trump's repeated warnings of military action to halt North Korea's nuclear weapons program, China has merged, moved and modernised its military operations.

The overhaul involves establishing a new border defence brigade, bunkers to protect against nuclear and chemical blasts, and 24-hour video surveillance of the mountainous frontier - including the use of hi-tech aerial drones.

China's military has also been preparing for a crisis in North Korea with helicopter gunships performing a live-fire drill in June and another in July using an armoured infantry unit equipped with new weaponry.

While China's Defence Ministry wouldn't directly acknowledge if the recent changes were connected to North Korea, a written statement provided to The Wall Street Journal said its forces "maintain a normal state of combat readiness and training" on the border.

Two Chinese J-10 fighter jets fly in formation. Photo / AP

Former senior US defence intelligence official for East Asia said he believed China's plans reach beyond border security.

"Once you start talking about efforts from outside powers, in particular the United States and South Korea, to stabilise the North, to seize nuclear weapons or WMD, in those cases then I think you're starting to look at a much more robust Chinese response," he said.

"If you're going to make me place bets on where I think the US and China would first get into a conflict, it's not Taiwan, the South China Sea or the East China Sea: I think it's the Korean Peninsula."

Despite the People's Liberation Army's efforts to bolster defences, a former US military attache in Beijing said China's military remains ill-prepared for a North Korean operation.

"I don't see the PLA at this time being particularly enthusiastic about being tasked to undertake a potential near-term mission in North Korea," he said.