Euan Graham, a security analyst with the Lowy Institute for International Policy in Sydney, told nine.com.au that while the rogue state would be overwhelmed in terms of conventional forces, it could be forced to deploy its nuclear and chemical arsenal.
And if North Korean leader Kim Jong-un feels a "decapitation" strike is imminent by the US and its allies, he could choose to move first.
Mr Graham said recent North Korean missile tests were really military exercises preparing for the rapid use of the warheads.
"These aren't missile tests, they are military exercises. North Korea knows the missiles work. What the military units are doing now practising, practising for a nuclear war."
He added that "going early and going nuclear" is part of the North Korean strategy.
Mr Graham explained that any American assault would entail a one to two-month bombardment of key military and nuclear installations by aircraft and sea-launched missiles.
Overwhelming air power would quickly dispose of North Korea's ageing air force and its few anti-aircraft missiles.
But he said the real risk for the US would be a widening of the conflict.
"The North Koreans have artillery along the border with the south that is capable of reaching Seoul. If that happened, South Korea which has a strong military would be compelled to get involved."
"Their nuclear missiles can also reach US bases in Japan and South Korea."
Reference: 9News
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