Donald Trump has mocked South Korean film Parasite and its best picture victory at the Oscars.

Director Bong Joon-Ho's searing commentary on class struggle made history at the Academy Awards this month when it became the first foreign language film to win the top prize.

On a memorable night, Parasite also earned Bong best director and won both best original screenplay and best international feature.

However, Mr Trump was not impressed and bemoaned the film's success during a rally in Colorado.

"How bad were the Academy Awards this year?" the president asked, prompting boos from the crowd.

"The winner is - a movie from South Korea! What the hell was that all about?