South Korea and Japan are considering whether they should build their own nuclear arsenals to counter the threat from North Korea, Henry Kissinger has said.

The former US national security adviser said he had little doubt nuclear weapons would spread across Asia as a result of the North's missile and nuclear programmes.

But Mr Kissinger, a Cold War nuclear strategist, told the New York Times: "If they [North Korea] continue to have nuclear weapons, nuclear weapons must spread in the rest of Asia."

Ri Yong Pil tells CNN the possibility of a nuclear threat from North Korea should be taken 'literally'

He added: “It cannot be that North Korea is the only Korean country in the world that has nuclear weapons, without the South Koreans trying to match it. Nor can it be that Japan will sit there.

“So therefore we’re talking about nuclear proliferation.”

The South and Japan fear Donald Trump's administration might hesitate to defend its allies if doing so might provoke a nuclear attack on the United States, the paper reported.

In South Korea, around 60 per cent of the population is in favour of building nuclear weapons.

Japan's Prime Minister, Shinzo Abe, who won a two-thirds majority in parliament, hopes to overturn Japan's post-war constitution in order to build up military forces against the potential threat from the North.

While public support for nuclear arms in Japan is low, that could change if both North and South Korea had arsenals.

Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb Show all 6 1 /6 Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb Photos released by North Korea show Kim Jong-un talking to subordinates next to a device thought to be the new thermonuclear weapon. There is no way of independently verifying the pictures STR/AFP/Getty Images Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb North Korea claims it has successfully tested an advanced hydrogen bomb which could be loaded onto an intercontinental ballistic missile AFP/Getty Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb A diagram on the wall behind Mr Kim shows a bomb mounted inside a cone STR/AFP/Getty Images Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb North Korean leader Kim Jong-Un (C) attending a photo session with participants of the fourth conference of active secretaries of primary organisations of the youth league of the Korean People's Army (KPA) in Pyongyang STR/AFP/Getty Images Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb A new stamp issued in commemoration of the successful second test launch of the "Hwasong-14" intercontinental ballistic missile KCNA via Reuters Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb A new stamp issued in commemoration of the successful second test launch of the "Hwasong-14" intercontinental ballistic missile KCNA via Reuters

General Mattis sought to reassure US allies in the region by saying North Korea is outmatched by the firepower and cohesiveness of the decades-old US-South Korean alliance.

"North Korea has accelerated the threat that it poses to its neighbours and the world through its illegal and unnecessary missile and nuclear weapons programs," he said, adding that US-South Korean military and diplomatic collaboration thus has taken on "a new urgency."