Pyongyang has rejected the report, describing it as a concoction by the United States and its allies, Japan and the European Union. But, the North appears to be willing to maintain a rapprochement with South Korea that may be crucial as it seeks food for its people.

Watch: An emotional moment for those separated by Korean war

“I am afraid my family in North Korea might still think I came to the South to live a good life for me alone,” said Kim, who fled south when he was 16, fearing US attacks on Pyongyang during the war.

“Before I die, I must explain that I did not abandon my family, that I was swept up by the refugee flow during the chaos. Resolving this misunderstanding is the first thing I want to do in person with my sister,” he said, adding that chemotherapy was working for him.

“My youngest brother Ha-choon had not even started school when I last saw him,” said Jang, the eldest of four siblings, one of whom has died.

“But now he’s an old man like me,” said the 81-year-old, sporting the light brown suit and maroon tie that he has bought for what he believes will be his last meeting with his remaining brother and sister, who remain in the North.

Conscripted by the North Korean army at the age of 19, Jang was captured and, when given a choice to return to his home in North Hamgyong Province near the Russian border, he opted to stay in the South.

The 82 frail South Koreans, two of them in ambulances, left for the North Korean border on Thursday. Ten coaches, with half a dozen police vehicles as escorts, left the eastern port city of Sokcho at 8.30am local time for the heavily militarised border 50 kilometres away.

The departure was delayed as two female members of the group needed medical attention, and ended up being placed into ambulances for the journey.

More than a dozen were in wheelchairs and needed help boarding the buses, which they shared with 58 family members, brought along for physical as well as emotional support.

After crossing the world’s last major cold war frontier, there was another 30-kilometre drive to a resort on Mount Kumgang - the venue for the emotional reunion with 180 North Korean relatives they have not seen for more than 60 years.

“I think when I see her face, I won’t believe it’s real,” Kim Dong-bin said of the elder sister he left decades ago in Pyongyang. “I wonder if I will be able to recognise her immediately? It’s been so long."

All carried bags stuffed with gifts, ranging from basic medicines, to framed family photos and packets of instant noodles. Some brought bags of fresh fruit which they planned to offer in a joint prayer ceremony with their reunited siblings to their late parents.

“The gifts I’m bringing to my sister should be good. Something you can’t see much in North Korea so I hope she will be happy,” said Kim Se-rin, 85.

“I’ve also included some US dollars for her and my younger brother,” Kim said.

The reunion event at Mount Kumgang was the result of tortuous, high-level negotiations between Pyongyang and Seoul, which nearly broke down over the North’s objections to overlapping joint military exercises between South Korean and the United States.

Millions of Koreans were separated by the 1950-53 war, and the vast majority have since died without having any communication at all with surviving relatives.

Because the conflict concluded with an armistice rather than a peace treaty, the two Koreas technically remain at war and direct exchanges of letters or telephone calls are prohibited.

The reunion programme began in earnest after a historic North-South summit in 2000, but the waiting list has always been far larger than the numbers that could be accommodated.

For many, time simply ran out, and last year alone 3,800 South Korean applicants for reunions died without ever seeing their relatives.

On Thursday, the mass reunion gathering in one of the resort’s main halls at around 3pm. There will be a dinner in the evening, and then private reunions between the divided relatives on Friday.

For all the joy the reunion brings, it is tempered by the realisation that, with an average age of 84, the farewell on Saturday will be final.

“This will be our first and last reunion,” Kim Dong-nin acknowledged, shaking his head.

All the South Korean participants had spent the night in a Sokcho hotel, where they were given an “orientation” course by South Korean officials listing a series of dos and don’ts for their stay in Mount Kumgang.

“They were basically telling people not to discuss any political issues and not to be swayed by North Korean propaganda,” said Kim’s wife, Shin Myung-Soon.

The emotional meetings with 180 North Korean relatives will last until Saturday, after which the South Korean group will return home.

Then a selected group of 88 North Koreans will travel to Mount Kumgang to meet 361 of their relatives from the South from this Sunday to next Tuesday.

The reunions used to be held roughly annually, but have not taken place for three years as tensions between the two Koreas spiralled higher after the South said the North sank one of its naval vessels in 2010. In later months, the North shelled a South Korean island and Pyongyang threatened nuclear attacks last year.

There have been 18 family reunions since the first in 1985 and a total of 18,143 South and North Korean brothers, sisters, fathers and mothers have met.

Of the 128,000 people registered in South Korea as coming from families that were torn apart by the Korean War, 44 per cent have already died and more than 80 per cent of survivors are over 70 years old, according to South Korea’s Unification Ministry, which handles inter-Korean relations.

This year the North demanded that South Korea and the United States halt military drills at the price of holding the reunions, although it later said it would allow them, opening a door to potential dialogue between Seoul and Pyongyang.

The possibility of food shortages could have been a factor.

“Now it’s almost March, when the new farming season must begin, and Kim Jong-un has no means to feed his people,” said Kim Seok-hyang, professor of North Korean studies at Ewha Womans University.

“He must get outside help. But looking around, the US won’t give him anything, China doesn’t seem willing to give anything and then there’s the UN human rights report pressuring him. The family reunions card is his last resort because he can’t neglect his people.”

The two sides have squabbled about the details of this reunion, such as the venue, and the North has always insisted they be held o n North Korean soil. 

“The North fears exposing their people to the outside world so they want to shroud their people from looking at the South’s successful way of life,” said Kim, the professor.

But South Koreans visiting the Mount Kumgang resort in the North have other issues in mind.

Kim, the cancer patient, has prepared gifts such as down jackets, socks and long johns for his sister. “Winters are harsher up in the North and we know that heating systems are crude there,” he said.

For the families, the politics are secondary.

“I swore to myself, I must not die before I meet my brother and sister,” said Jang, the 81-year-old. “I just cannot die with my eyes closed if I don’t see them this time.”