North Korea's ruling family has long dreamed of a state-of-the-art rail system linking its major cities with each other and the wider world.

Now leader Kim Jong Un is looking to capitalize on an easing in international tensions to advance plans for a high-speed rail network to rival those in Europe and South Korea.

Kim has instructed officials to seek partnerships with countries such as South Korea and France, according to a South Korean broker with knowledge of the matter and a senior North Korean diplomat.