Actress Jessica Chastain in the film Zero Dark Thirty (HANDOUT)

Actors Martin Sheen and Ed Asner are urging Oscar voters to boycott Zero Dark Thirty over the film's torture scenes.

The film, which shot to number one at the U.S. box office over the weekend, and star Jessica Chastain are both up for Academy Awards next month, but many film fans have been turned off by director Kathryn Bigelow's decision to include graphic scenes of U.S. intelligence chiefs waterboarding and humiliating detained terrorists for information.

Sheen and Asner have joined a list of actors protesting the movie, claiming it "glorifies torture".

Bigelow and her screenwriting partner Mark Boal have also come under fire from top U.S. politicians, who fear the torture scenes in the film were created using classified information about the techniques used to extract information from detainees.

In the movie, one terrorist character was stripped in front of Chastain's CIA Agent and forced to crawl around on all fours like a dog. In another scene, water is poured over a damp cloth placed over his nose and mouth during an interrogation in what has become known as waterboarding and depriving the victim of oxygen.

Chastain is a favourite to win the Best Actress award at the Oscars after picking up Critics' Choice and Golden Globe accolades.