Basketball hall-of-famer Dennis Rodman, who forged an unlikely friendship with North Korean leader Kim Jong-Un on a recent trip, appealed Tuesday for the freedom of an American sentenced to 15 years.

"I'm calling on the Supreme Leader of North Korea or as I call him 'Kim', to do me a solid and cut Kenneth Bae loose," Rodman tweeted.

Bae, whose Korean name is Pae Jun-Ho, was sentenced last week to 15 years of hard labor on charges that he tried to topple the North Korean regime. The Korean-American had organized tours into the isolated state.

North Korea said it was not looking for a US emissary to seek Bae's release. Former presidents Jimmy Carter and Bill Clinton have both traveled to North Korea and met the leadership to secure the freedom of previous detained Americans.

Seoul-based activist Do Hee-Yoon has told AFP he suspected Bae was arrested because he had taken photographs of emaciated children in North Korea as part of efforts to appeal for more outside aid.

The specialized news site NK News reported that Bae was using his tour company to bring Christian missionaries into North Korea, which strictly forbids religious proselytizing.

Rodman, the famously flamboyant and tattooed former NBA star nicknamed "The Worm," in February became the only prominent American to meet North Korea's young leader Kim Jong-Un who succeeded his late father in December 2011.

While some pundits welcomed the rare interaction between the two countries, Rodman faced ridicule in much of the US media which accused him of ignoring human rights and bolstering one of the world's most oppressive regimes.

Rodman during his trip told Kim, "You have a friend for life," after a game between a North Korean team and a US side featuring members of the Harlem Globetrotters ended in a diplomatic 110-110 tie.

The Swiss-educated Kim, believed to be in his late 20s, is reported to be a huge fan of basketball and the Chicago Bulls, with whom Rodman won three NBA titles alongside Michael Jordan in the 1990s. (AFP)