One of Kim Jong-un's top aides has not been seen for months and may even have been executed after being accused of 'impudence', it has been claimed.

Kim's former confidante Hwang Pyong-So vanished as part of a purge of senior military figures in North Korea during a bid by the dictator to reduce the influence of the powerful army.

Hwang, the head of the military's powerful General Political Bureau, was once seen as the second most powerful man in the secretive country.

Former friends: 'Punished' military leader Hwang Pyong So, left, stands near North Korean leader Kim Jong Un in this April, 2017 photo

But he was last seen in public in early October at a gymnastics gala and, according to South Korean newspaper, JoongAng Ilbo, it is not known if he is still alive.

Since taking power in 2011, North Korea's young leader has brutally removed anyone perceived as a potential challenge to his authority, including ordering the execution of family members.

But observers say the latest move appears aimed at curbing the overgrown influence of the military, which blossomed under his late father Kim Jong-Il's Songun (military-first) policy.

Last month it was reported that Hwang Pyong-So and his deputy Kim Won-Hong, had been punished for 'impudence' towards the ruling Korean Workers' Party, which Kim Jong-Un heads.

'This is another Kim Jong-Un play aimed at tightening his grip on, and taming, the military,' Yang Moo-Jin, a professor at the University of North Korean Studies, told AFP.

Kim is moving away from the Songun policy and 'reaffirming the principle that the party is always above the military' Yang said.

Professor Koh Yu-Hwan at Dongguk University added: 'The Songun policy has always been a double-edged sword and Kim is reorganising the military that became overgrown under his father and is restoring the system of party dominance.'

Rivals: The investigation of the military political bureau which allegedly led to the punishment of Hwang Pyong So, left, was spearheaded by Choe Ryong Hae, pictured right

The NIS said the level of punishment meted out to the two men was not known, but South Korean lawmakers who attended the closed-door briefing suggested they might have been sent to provincial farms for re-education through labour.

Hwang was once seen as the second most powerful man in North Korea.

He led the high-level delegation that visited the South during the Incheon Asian Games in 2014, and made his last public appearance in October.

Kim Won-Hong had returned to office earlier this year after being sacked as minister of state security, for power abuse and corruption in mid-January.

Kim, who served as the spy chief since 2012, had played a key role in arresting and executing Kim Jong-Un's uncle Jang Song-Thaek four years ago.

The North's leader has reportedly killed more than 100 military, party and government officials, including Jang and Hyon Yong-Chol, a former defence chief who was put to death in 2015.

South Korea believes he was also responsible for the Cold War-style assassination of his half-brother Kim Jong-Nam, who was poisoned at a Malaysian airport earlier this year.