China's state broadcaster is investigating one of its hosts after a video of him insulting Mao Zedong was leaked online, causing a stir and rekindling debate on the complicated legacy of the father of communist China.

China Central Television says talent show host Bi Fujina will face serious investigation because his jokes have had a "severe social impact."

In the home video that circulated widely online before censors removed it this week, Bi sings a song about Communist Party-led soldiers battling bandits in northeastern China in the 1940s. To the laughter of guests at a dinner, Bi adds his own commentary in a speaking voice between lines.

When the lyrics referred to Mao, Bi called the revolutionary leader a vulgar phrase and said "he has ruined us all."