South Korea's National Intelligence Service (NIS) told the country's Parliament in a briefing Tuesday that they believe Choe Ryong Hae was sent to a farm in the North Korean countryside in early November, Shin Kyung-min, a lawmaker who was present during the briefing, told CNN Tuesday.
The reason for his exile is not known but the NIS said it may be because of differences of opinion with Kim, or because of the poor quality of construction of the Baekdusan Power Plant
, said to be part of Choe's remit.
But experts say his disappearance may just be temporary -- Choe has been purged and re-instated at least once before.
"It's not that serious," said Professor Andrei Lankov of Seoul's Kookmin University. "If it's serious he will be killed."
He added that North Korea has used re-education for less serious crimes since the late 1950s. "As long as the person works hard and never forgets to proclaim loyalty to the government and the world's greatest leader, they are usually recalled and often re-promoted to a high position."
A good example of this was Kim's uncle, Jang Song Taek, who fell from grace a number of times before being re-instated. His most recent dismissal was final however, as Pyongyang announced Kim had him executed in December 2013 for allegedly acting against the state.
Choe is believed to be North Korea's point person on China after he met Chinese President Xi Jinping in 2013, acting as Kim's envoy.
Choe also made a surprise visit to South Korea in October last year for the closing ceremony of the Asian Games.
Speculation has surrounded Choe's whereabouts for several weeks after he was not named as part of a funeral committee for a marshal in North Korea's military.