South Korean President Moon Jae-in  (Xinhua/NEWSIS)

South Korean President Moon Jae-in on Tuesday proposed that the United Nations create an "international peace zone" to replace the peninsula's divide, saying the idea would both reassure the North and inspire the world.

The left-leaning leader, whose diplomacy paved the way for historic summits between US President Donald Trump and North Korean leader Kim Jong-un, laid out his rosy vision for the last Cold War frontier in an address to the UN General Assembly.

He asked the international community to commit to designating the international peace area to replace the 250-kilometer Demilitarized Zone that has split the two Koreas for more than 60 years.

Moon said the zone would offer an added incentive for Kim to give up nuclear weapons, the focus of more than a year of on-again, off-again talks between North Korea and the US.

"The establishment of an international peace zone will provide an institutional and realistic guarantee for North Korea's security," Moon said.

"At the same time South Korea will be able to gain permanent peace," he said.

Moon voiced hope that the zone, which is four kilometers wide, would become the home of UN agencies dedicated to conflict resolution and the environment and eventually be declared a world heritage site by UNESCO, the UN cultural body.

"It can become an international peace zone in name as well as substance," Moon said.

Despite the intense military buildups on each side of the Demilitarized Zone, "paradoxically it has become a pristine ecological treasure trove," he said.

"When the DMZ that cuts the midriff of the Korean peninsula is turned into a peacezone, the peninsula will evolve into a bridge nation that connects the continent and the ocean and facilitates peace and prosperity," he said.