China must urgently consider cutting its oil exports to North Korea by at least half to force the isolated regime to “change course” on its nuclear and ballistic missiles programmes, the former secretary general of the United Nations, Ban Ki-moon, has said.

Ban’s comments in an exclusive interview with This Week in Asia echoed US Secretary of State Rex Tillerson, who on Tuesday said further unilateral Chinese oil sanctions – which would go beyond those mandated by current UN resolutions – were the surest way to force Pyongyang to the negotiating table.

“Given the extraordinary pace of the situation unfolding before us, China needs to at least consider a partial embargo – say half of its exports – if we want to change the current course that North Korea is on,” Ban said a day before his three-day visit to Hong Kong.

The veteran diplomat and Julia Gillard, the Australian former prime minister, are to address the Asia Society Hong Kong’s gala dinner on Thursday.

Ban acknowledged that a complete embargo was anathema to Beijing, which fears the collapse of Kim Jong-un’s regime would bring instability and a flood of refugees to its shores.

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China has said international efforts to pressure Kim to back down from his nuclear ambitions must adhere to a ‘four noes’ policy: no regime change, no regime collapse, no accelerated reunification, and no military deployment anywhere north of the 38th parallel that divides the Korean peninsula.

While there is no publicly available data on North Korea’s energy use and imports, the US energy agency EIA estimates that in 2016 the country imported around 6,000 barrels of oil products a day from China.

That figure is about 40 per cent of the North’s estimated total daily oil consumption of 16,000 barrels, itself a drop in the ocean compared to South Korea’s consumption in 2016 of 2.6 million barrels a day.

Crude oil is carried from China to North Korea via the 30km “Sino-DPRK Friendship Oil Pipeline”, which has been in operation since 1975.

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In a speech on Tuesday at the Atlantic Council think tank in Washington, Tillerson said President Donald Trump “would like to see China cut the oil off”.
“The last time the North Koreans came to the table, it was because China cut the oil off. Three days later the North Koreans were at the table talking,” he said.

Despite the tightrope situation facing Chinese leaders, Ban hoped Beijing would “wisely and tactfully play a vital role in utilising its power to ensure the international community’s safety from any impending security threat”.

With Washington officially stating that Pyongyang could be just months from gaining the ability to strike the US mainland, Ban said the superpower was facing its “most serious security challenge since the end of the cold war”.

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“For South Korea, this is the most dangerous security crisis since the Korean war in 1950,” Ban said.

He added: “The US’ determined will to deter North Korea’s security threat at all costs is undoubtedly loud and clear. As the current situation seems to be evolving into a collision course, it would be wise for North Korea to take note of the serious repercussions their actions may [have].”

Pyongyang has made no indication it will change tack, however.

On Tuesday, state news agency KCNA reported Kim as saying the isolated country would “victoriously advance and leap as the strongest nuclear power and military power in the world”.

Such sabre rattling has intensified following the November 29 test launch of the Hwasong-15 ICBM, which Pyongyang claims can land a nuclear warhead anywhere in the US.

Subsequent UN Security Council sanctions on North Korea limit imports of refined petroleum products to two million barrels a year, a cut the US says amounts to about 30 per cent of Pyongyang’s oil intake.

Washington had initially demanded a complete oil embargo, but Russia and China – veto-wielding members of the Security Council – were not in favour.