North Korea says it is putting an American citizen on trial for allegedly trying to overthrow its government.

Korean-American Kenneth Bae, 44, was detained in the north-east city of Rajin last November while leading a tour group there.

A number of US citizens of Korean descent have run into trouble in North Korea in the past and Pyongyang used their detention to extract visits by high-profile American figures.

In 2009, former US president Bill Clinton flew to Pyongyang to meet then-leader Kim Jong-il before securing the release of two American media workers who had been charged with entering the country illegally.

International diplomacy expert Ralph Cossa says Pyongyang is likely trying to elicit the same response at a time of heightened tension.

"I don't think anyone believes that they're doing this because they really think he's guilty," he said.

"They're doing this because they want to find a way to probably get another high ranking American [to visit].

"Last time they had a couple of Americans on trial they got Bill Clinton to come and save them.

"Maybe they're holding out for Hillary this time, who knows?"

The North's official news agency says Bae has admitted to the charges, which carry a punishment of five to 10 years' hard labour.

"In the process of investigation he admitted that he committed crimes aimed to topple the DPRK with hostility toward it," KCNA state media reported.

"His crimes were proved by evidence."

'Political pawn'

There are reports in a South Korean newspaper that Pyongyang may have taken issue with some of Bae's photographs, including pictures of homeless children.

Another newspaper reported he may have been carrying footage of North Korea executing defectors and dissidents.

The White House says it is aware of the situation.

Representatives of the Embassy of Sweden, which acts as the protecting power for US citizens in North Korea, visited Bae on Friday.

Dictator Kim Jong-un has upped North Korea's fiery rhetoric in recent months. ( Reuters/KCNA )

Former UN ambassador Bill Richardson hopes the trial might help lead to Bae's release.

"Hopefully the conclusion of the legal process for Kenneth Bae will set the stage for a release on humanitarian grounds," he said.

"He should not become a pawn in the current American-North Korean friction."

Mr Richardson delivered a letter regarding Bae to officials during a trip to North Korea in January, but he was unable to meet with him.

Tensions between North Korea and the United States have spiralled in recent weeks.

Pyongyang has been threatening nuclear attack in response to United Nation sanctions and joint South Korean-US military drills.

Analysts say this trial is simply more political theatre.



ABC/Reuters