The casting of the upcoming film "Exodus: Gods and Kings" continues to be a source of controversy for its stars and director.

The action film is an adaptation of the biblical story of Moses—a Hebrew who was adopted by the Pharaoh's daughter, and frees the Israelites from Egyptian slavery. While white actors were cast in the lead roles, black actors were cast as slaves.

The Ridley Scott-directed movie features Christian Bale as Moses, Sigourney Weaver as his adopted mother, Queen Tuya, John Turturro as Pharaoh Seti, and Joel Edgerton as Moses' adopted brother, Ramses II.

Bloggers and Twitter users quickly protested the cast's lack of diversity.

"The servants, thieves and assassins are played by Africans," Medium blogger David Denis wrote. "To make the main characters white and everyone else African is cinematic colonialism."

"It's White Moses Versus White Pharoah [sic] Saving A Bunch Of White Guys From The Other Bunch Of White Guys, None Of Whom Should Actually Be White," read a headline on movie blog site Twitch.

"In 'Exodus' did nobody ever once tell the cast and crew that having Africans as slaves to white pharaohs was a bad idea?" a Twitter user wrote, adding the identifying hashtag: "#BoycottExodusMovie."

There is also a Change.org petition asking people to boycott the film.

"The Bible says both Egyptians and Ethiopians are descendants of Ham," the petition reads. "Remember, Egypt wasn't invaded by Rome until 300 BC. Egypt is in Africa not Europe."

It has received 561 signatures.

When questioned about the controversy at the Melbourne International Film Festival, Edgerton distanced himself from the issue.

"I do understand and empathise with that position," he said, adding, "It's not my job to make those decisions. I got asked to do a job, and it would have been very hard to say no to that job."

The iconic film "The Ten Commandments" also had an all-white cast. The film starred Charlton Heston as Moses, Yul Brynner as Ramses, and Anne Baxter as Nefertiti. The racial climate, number of black actors, and opportunities provided to them were very different in 1956, however.

"Getting light-complexioned actors to play the roles of dark-complexioned historical figures is not only a sign of blatant disrespect to the persons they are portraying but it is also disrespectful to their families, to history and to the intelligence of the audience," another petition reads. "For too long Hollywood has gotten away with revisionist history."

Ridley Scott has not publicly responded to the controversy.