SEOUL (AFP) - North Korean leader Kim Jong Un has pushed out a high-profile military figure who once played a key role under his late father - the latest in a series of top-level personnel changes.

The Korean Central News Agency (KCNA) identified a new figure, Jon Chang Bok, as first vice-minister of the People's Armed Forces Ministry in a report on Thursday which detailed Mr Kim's trip to an army food-processing factory.

The People's Armed Forces Ministry is essentially the defence ministry and comes under the control of the powerful National Defence Commission.

KCNA did not say when Mr Jon, a relatively little-known figure, was appointed to the post, but he replaces Vice Marshal Hyon Chol Hae.

Mr Hyon, 79, was regarded as one of the North's top military figures who helped support the young leader following the death of his father, Kim Jong Il, in December 2011.

But Kim Jong Un has reshuffled his military top brass in an apparent attempt to secure his leadership since taking over the reins of power.

In changes disclosed on Sunday, Jang Jong Nam, a relatively young field commander believed to be in his mid-50s, replaced hawkish defence minister Kim Kyok Sik.

Mr Kim Kyok Sik, appointed six months ago, had been seen as a hardline choice given that he was widely believed to have directed the 2010 shelling of a South Korean border island.

Mr Jang, who will now have Mr Jon as his number-two, is not the most senior figure in the Korean military. The National Defence Commission is chaired by Kim Jong Un as supreme commander.

And despite the shake-up, other old-guard figures remain in influential positions in the commission and other leadership bodies.

The changes come as the Korean peninsula emerges from a period of highly elevated military tensions that followed the North's nuclear test in February.