South Korea's blueprint for railroad links through North Korea to China and Russia falls well short of Kim Jong Un's vision for developing his impoverished nation, according to a defector who provides economic research to the government in Seoul.

While President Moon Jae-in's so-called "three-belts" transport plan would benefit the North, given the poor state of its infrastructure, what the regime in the Pyongyang really wants is to ramp up special economic zones across the country, said Kim Byeong-uk.

"Installing new infrastructure, sure that's good. But it's an old plan," said Kim, who teaches North Korean studies at Dongguk University in Seoul and runs a small private economic research firm. "What South Korea wants is to connect the Korean Peninsula to reach out directly to Russia and China, but what the North primarily wants is to shore up its own economy by bringing in more money from overseas to its special economic zones."