Exile groups, who oppose the military junta in Myanmar, have suggested that Yangon has buried the hatchet because it wants to get its hands on North Korean nuclear and ballistic missile technology.
However, analysts dismiss this, and say the explanation could be as innocent as two left-leaning, secretive Asian countries with few other friends wanting to have a proper relationship.
Neither country, among the poorest and most isolated in the world and both subject to Western sanctions has shed any light on the reasons for the reconciliation.
"There are two levels to this: one is that the Burmese are normalising an abnormal diplomatic situation; the other that they are expecting to get something out of it - either in weapons or technology," said Trevor Wilson, a former Australian ambassador.
In 1983, more than 20 people, including four visiting South Korean ministers, were killed when North Korean agents said to have direct links to current leader Kim Jong-Il blew up a major Yangon landmark.