North Korea angrily denies that Kim Jong-un has had plastic surgery

North Korea has responded to persistent rumours that leader Kim Jong-un had plastic surgery to look like his revered grandfather, issuing an angry denial against "sordid" media reports.

Speculation that Kim's resemblance to the country's founding leader, Kim Il-sung, is not 100 per cent natural has been around for some time, though with little or no supporting evidence.

The rumours have been partly fed by the fact that Kim Jong-un has sought to evoke memories of his grandfather in numerous ways, through his style of dress, haircut, gestures and public appearances.

And there is a clear physical resemblance. But Pyongyang's patience with reports of plastic surgery appears to have run out.

"The false report … released by enemies is a hideous criminal act which the party, state, army and people can never tolerate," the official Korean Central News Agency (KCNA) said in a commentary on Wednesday.

Insisting that the very idea of Kim, who is in his late 20s, undergoing plastic surgery was "unimaginable", said KCNA flatly rejecting, what it described as "sordid hackwork by rubbish media".

Although the focus of the commentary's fury was the South Korean media, it seems Pyongyang's anger was triggered by a Chinese report last week that was widely picked up by newspapers in the South.