NBA-ICON-TURNED-DIPLOMAT Dennis Rodman has asked Kim Jong Un to "do me a solid" and release American prisoner Kenneth Bae.

"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 on Tuesday.

Bae, a devout Christian who worked as a tour operator near the China-North Korea border, was sentenced to 15 years of hard labour earlier this month for undisclosed "hostile acts" against the hermit kingdom.

Rodman visited North Korea in a March trip widely condemned by US officials, watching basketball with the Supreme Leader and going so far as to call Kim a "friend for life."

He said he tweeted for Bae's release after reading a Seattle Times blog post calling on him to do so.

"In direct response to your article headline, Ok. Read your story @uscthanhtan, and I decided to help," Rodman tweeted after his initial message to Kim.

In the post from late last week, blogger Thanh Tan told Rodman to "practice some real basketball diplomacy and call up his so-called friend for a favour".

"Perhaps now is the retired player's chance to use his notoriety for something other than to over-inflate his ego," Tan wrote.