The only way to solve the Korean crisis is to remove the regime, says a South Korean-born US writer who spent six months undercover in North Korea.

Suki Kim worked in North Korea teaching English at a university for the ruling class, later writing a book about her experience, called Without You, There Is No Us: Undercover among the Sons of North Korea's Elite.

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As the international community tries to put pressure on the North Korean regime with economic sanctions, she said that was no way to deal with Kim Jong-un.

"Literally the only way to approach it is a regime change, North Korea as a regime will not cooperate, you cannot actually come to any conclusion dealing with [their] great leader system," she said.

"North Korea does not honour any kind of negotiations, even if they say they'll do one thing they'll do something else. [North Korea] is just a land of lies, [it] does not honour truth.

"This is now the world's problem, not just the Korean problem — this is a nuclear threat."

North Korean leader Kim Jong Un provides guidance on a nuclear weapons program. ( Reuters: KCNA )

Ms Kim said under the leadership of Kim Jong-un there might be a possible crack in the belief of the people, one big enough that could be used as a way to break his control over North Koreans.

"The fact that Kim Jong-un is reckless, he doesn't seem to quite have the support of the people the way his father and grandfather did, I think that's actually one light of hope," she said.

In North Korea, Mr Kim's Jong-un's family are seen as "divine figures", and so by killing off family members Ms Kim said he potentially destroyed the very idea of divineness.

"These divine people who should be immortal, he made them mortal by murdering them," she said.

"So when that happened, I remember thinking this is actually an incredibly important thing that just happened because it shows … this great leader system could end because of his stupidity."

Ms Kim says Kim Jong-un is seen by many as a more reckless leader than his father. ( Reuters: KCNA )

'Reckless nature could be his undoing'

Ms Kim said Kim Jong-un's age, the fact he had not gained the same respect from the people as his father and that he appeared to be more reckless than past leaders could be enough to undo his power.

"Perhaps if the world can somehow pour enough information into North Korea there could be [enough] will within [the country] to no longer want this guy," she said.

She suggested the other countries work together to find ways to smuggle sources of information about the outside world into the country, such as DVDs and USB drives.

"Trying to actually reach into the world's biggest cult and having those people change is nearly impossible," she said.

"But because nothing else works, that is about the only thing one can hope, where the system erupts from the will of the people.

North Korea has the biggest army in the world. ( Reuters: KCNA )

"The only hope would be if the system ends. Because this system, the way it is, cannot be moderated."

Ms Kim said there was no way North Korea could move in the same direction as countries like China and Cuba, who both slowly moved closer to capitalism over the years.

"[But] you can't moderate a god, it's a fundamental god, you're asking a cult fundamental god to be half of a god, half of a cult — that doesn't happen," she said.

"There's nothing else, because the other thing is stand still, this just continues and continues and continues while 25 million people basically perish in there.

"Or nuclear war — none of these options, they're all catastrophes."

In North Korea Kim Jong-un's family are seen as "divine figures". ( Reuters: KCNA )

A generation dying from heartbreak

Ms Kim has her own connection to North Korea, just like thousands of other South Koreans.

"Millions of Koreans were separated during the Korean war. Our family was one of them, my grandmother lost her son who was 17 at the time," she said.

"This is not unusual, the tragedy of Korean division — which people actually forget — at the core of this problem goes back to millions of families being separated by force overnight."

She said her grandmother never stopped waiting for her son to return after he was taken to the North.

"She never moved and waited and waited and died waiting for him," she said.

"And I can't imagine anything more tragic than an entire nation basically dying of heartbreak, and that's what happened to that generation."

Ms Kim decided to travel to North Korea in 2011, saying she realised the only way to truly understand the world across the border was to be "embedded in it."

Suki Kim teaching a class, 2011 ( Suki Kim )

She lived for six months there, spending all of her time within the university with children of the North Korean elite.

"What really shocked me was the level of surveillance and clear lack of freedom, and this idea of cult leadership of the great leader," she said.

"In North Korea [2011] was the year 100, because [their] calendar system began with the birth of the original great leader.

"Children of the ruling elite knew nothing abut the outside world.

Ms Kim said while they were smart young men who were able to process information well, as well as learn English quickly, they often said things to her she described as 'nonsensical'.

"They would say … [they] cloned a rabbit when they were in fifth grade, and clearly they didn't clone a rabbit," she said.

"They repeated that because that's what they've been told.

"This is how cults work. You repeat the stories that seem impossible — realistically and scientifically — but part of you believes it because that's what your faith system is."

But she said she could see the cracks within the cult belief, with many of her students showing signs of curiosity about the outside world — although they could not show it openly as everyone constantly monitors each other.

"Sometimes they would be curious why there's more than one television channel in the rest of the world, whereas they only have one," she said.

"But even if there's a crack, accompanying this cult ideology is also a brutal dictatorship.

"Everybody watches everyone. There's a meeting every North Korean has to attend once a week where they report on each other.

"So even if there are cracks, you also can't pursue that crack. It's not possible there because of the surveillance of constant fear."