NORTH Korea has broadcast images of the moment Jang Song-Thaek - the once-powerful uncle of young leader Kim Jong-un - was turned on.

NORTH Korea has broadcast images of the moment Jang Song-Thaek - the once-powerful uncle of young leader Kim Jong-un - was turned on.

Jang has been purged and some reports suggest he has been executed.

State TV on Monday showed photos of Jang being dragged out of his seat at a meeting by two officers - an extremely rare publication of humiliating images involving a senior official. It was not certain if the incident happened at Sunday's meeting. But the TV aired other photos from Sunday showing a stony-faced Kim sitting at the podium with other top officials.

North Korea has also edited Jang out of official images and propaganda documentaries.

The official news agency KCNA accused the man once seen as the power behind the throne of being a corrupt, drug-taking womaniser bent on building his own faction in the ruling party.

South Korean analysts predicted a sweeping purge would follow, leaving Kim as the undisputed centre of power.

Free North Korea Radio - a Seoul-based radio station run by North Korean defectors - claimed Jang has already been executed. Citing high-level sources in the North, it claims Jang and six other party and military cadres who were close to him had been executed on Thursday in the capital Pyongyang.

KCNA said Jang, once seen as his nephew's mentor, had been stripped of all his posts and of party membership for committing criminal acts and leading a "counter-revolutionary faction".

Analysts said Jang's main role had been to ensure a smooth transition after the inexperienced Kim Jong-un came to power following the death of his father Kim Jong-il in December 2011. But they said Jang had become increasingly resented by the leader, who is aged about 30.

"Jong-un has built a solid power base for the past two years, and he no longer needed a regent who appeared to be increasingly powerful and threatening," said Paik Hak-Soon, a researcher at the South's Sejong Institute think tank.

KCNA said the meeting on Sunday confirmed it had "eliminated Jang and purged his group, unable to remain an onlooker to its acts any longer".

The regime said it removed Jang and his associates for trying to build a faction within the party, and for appointing his followers to top positions to serve his own political ends.

The KCNA report said Jang "had improper relations with several women and was wined and dined at back parlours of deluxe restaurants", becoming "affected by the capitalist way of living".

Jang was also accused of hindering North Korea's state-run production of iron, fertilisers and vinalon - a homemade synthetic fibre - by selling off resources at cheap prices and "throwing the state financial management system into confusion".

Jang has fallen out of favour before. In 2004 he was understood to have undergone "re-education" as a steel mill labourer because of suspected corruption, but he made a comeback the following year. Jang expanded his influence rapidly after Kim Jong-il suffered a stroke in 2008, leaving his health impaired.

He was appointed vice chairman of the nation's top body, the National Defence Commission, in 2010.

His wife Kim Kyong-Hui, who is Kim Jong-il's sister, has also long been at the centre of power. She was promoted to four-star general at the same time as Kim Jong-un in 2010.

The pair were once viewed as the ultimate power couple in Pyongyang. But in the past year Kim Kyong-Hui has been less visible, with reports that she was seriously ill and had sought hospital treatment in Singapore.

"This time, Jang is gone for good. He'll never be allowed into politics again," said Paik from the Sejong Institute.

Seoul was "closely monitoring" the situation in the North, said unification ministry spokesman Kim Eui-Do.