The eldest son of late North Korean leader Kim Jong Il questions his half brother's ability to lead the reclusive regime, and predicts failure in a new book set for release in Japan this week.

Titled "My Father, Kim Jong Il, and Me," the book is based on reported interviews and emails between Japanese journalist Yoji Gomi and Kim Jong Nam, over a seven year period. It offers a revealing look at the inner workings of the Kim family.

On the issue of succession, Kim Jong Nam says his father initially opposed the hereditary transfer of power, saying it would damage his accomplishments, along with those of his father Kim Il Sung, the late leader. He eventually changed his mind, convinced that a continuation of the Kim family line was necessary to maintain stability in North Korea.

"The dynastic succession is a joke to the outside world," Kim Jong Nam says in the book, according to excerpts published by the South Korean daily, Chosun Ilbo. "The Kim Jong Un regime will not last long."

Kim Jong Nam says his half brother was tapped to be the next leader solely because he physically resembled his grandfather. He reveals he has never met Kim Jong Un.

"Without reforms, North Korea will collapse, and when such changes take place, the regime will collapse," he says. "I think we will see valuable time lost as the regime sits idle fretting over whether it should pursue reforms or stick to the present political structure."

Kim Jong Nam has made no secret of his rift from the rest of the Kim family. Known as a playboy, the eldest son spends much of his time in Macau. He was arrested in 2001, after he tried to sneak into Japan with a fake passport to go to Tokyo Disneyland, falling out of favor with his father. The eldest son was largely absent from any of Kim Jong Il's official funeral coverage, which aired on North Korea's state media.

Still, Kim Jong Nam says ideological differences, not his personal lifestyle, caused his father to turn against him.

"After I went back to North Korea following my education in Switzerland, I grew further apart from my father because I insisted on reform and market-opening and was eventually viewed with suspicion," he says. "I told him honestly how the international community was concerned about the nuclear tests and missile launches and I am asking him to train my brother well in order to ensure a good life for the people."

Kim Jong Nam also discusses Pyongyang's deadly shelling of Yeonpyeong island in 2010, calling it a provocation that allowed the North Korean military to "justify their status and existence and possession of nuclear weapons."