North Korea's most senior defector for over two decades says the country's leader Kim Jong-un is prepared to use nuclear weapons on his enemies and must be "eliminated".

The 33-year-old despot is locked in an escalating war of words with the United States, and its neighbours to the south over Pyongyang's repeated missile launches.

But the Democratic People's Republic of Korea (DPRK) believes it has the right to pursue a nuclear programme, despite widespread poverty and international sanctions, with US President Donald Trump saying that Washington may have to "deal" with the hermit nation.

Now defector Thae Yong Ho, former deputy ambassador to London says - as the state prepares for another long-range missile test - that the world should be prepared for Kim to react.

"Kim Jong-un is a man who can do anything beyond the normal imagination," he warned according to NBC News on Sunday. Adding the "real solution to the North Korean nuclear issue is to eliminate Kim Jong-un from the post".

He continues saying that Kim is "desperate in maintaining his rule by relying on his [development of] nuclear weapons and ICBM (Intercontinental Ballistic Missiles).

"Once he sees that there is any kind of sign of a tank or an imminent threat from America, then he would use his nuclear weapons with ICBM."

North Korea Kim Jong-un missiles
7 March 2017: North Korean leader Kim Jong-un acknowledges the applause as he supervises the launch of ballistic rockets KCNA/Reuters

As the rhetoric between Washington and Pyongyang intensifies Thae said that the country has reached a "very significant level" of development.

"If Kim Jong-un has nuclear weapons and ICBMs, he can do anything ... so I think the world should be ready to deal with this kind of person."

The 54-year-old regularly appears before global media to express his views on his home country and has previously said Pyongyang are aiming to complete its development of nuclear weapons by the end of 2017.

In total the DPRK has staged five nuclear tests - two of them last year - of long range missiles that could, in theory, strike the US.

The tests have also angered Japan as many of the missiles have landed in the Sea of Japan, that divides the two nations.

Trump warned in an interview with the Financial Times that the US is prepared to act unilaterally to deal with North Korea's nuclear program if China will not assist.

"Well, if China is not going to solve North Korea, we will. That is all I am telling you," he said.