North Korean leader's uncle purged
North Korean leader Kim Jong Un attends a meeting of the ruling Workers' Party politburo in Pyongyang in this undated photo - (KCNA/Reuters)

Pyongyang has begun a "reign of terror" with the purge of the uncle of North Korean leader Kim Jong-un and the volatile relations between two Koreas are likely to deteriorate in the near future, says South Korean president Park Geun-hye.

Even as North Korea confirmed that Kim's uncle Jang Song-thaek, a major powerbroker in the communist regime, had been purged, Park warned that the move would further destabilise the Korean peninsula.

"North Korea is engaged in a reign of terror while carrying out massive purges in order to consolidate Kim Jong-un's power. The South-North relations could become more unstable in the future," he told a cabinet meeting.

"We are at a very important point in history. Situations on the Korean peninsula and in northeast Asia are changing rapidly and we are in a situation where we can't lower our guard against North Korean threats and changes in its situation."

In a dramatic public purge shown on national television, Jang was marched out of a meeting of generals and was stripped of all his power by Pyongyang. He was accused of being involved was involved in "anti-party" and "counter-revolutionary factional" activities. Jang's associates were believed to have been executed on similar charges.

The public removal of such a high-profile figure was the first major shakeup since Kim took over as the leader on the death of his father, Kim Jong-il, in 2011.

"In the months to come, Kim is highly likely to oust all Jang's followers that still have substantial influence in the North Korean government military," Son Tae-gyu, professor at Dankook University, told the Korea Times.

"To divert attention, Kim could rely on aggressive measures such as violations of the Northern Limit Line (NLL), missile launches and threats to carry out another nuclear test."