Near the end of the film Avatar, the villain snarls at the hero, “How does it feel to betray your own race?” Both men are white — although the hero is portrayed as a blue-skinned, 9-foot tall, long-tailed alien.

Strange as it may seem for a film that pits greedy, immoral humans against noble denizens of a faraway moon, Avatar is being criticised by a small but vocal group of people who allege it contains racist themes — of a white hero once again saving primitive natives.

Since the film opened to widespread critical acclaim three weeks ago, hundreds of blog posts, newspaper articles, tweets and YouTube videos have made claims such as that the film is “a fantasy about race told from the point of view of white people” and reinforces “the white Messiah fable.”

The film’s writer and director, James Cameron, says the real theme is about respecting others’ differences.

In the film (Warning: spoilers ahead) a white, paralysed Marine, Jake Sully, is mentally linked to an alien’s body and set loose on the planet Pandora. His mission: persuade the mystic, nature-loving Na’vis to make way for humans to mine their land for unobtanium — a mineral worth $20 million per kilo back home.

Like Kevin Costner in Dances with Wolves and Tom Cruise in The Last Samurai or as far back as Jimmy Stewart in the 1950 Western Broken Arrow, the hero (Sully) switches sides. He falls in love with the Na’vi princess and leads the bird-riding, bow-and-arrow-shooting aliens to victory over the white men’s spaceships and mega-robots.

Adding to the racial dynamic is that the main Na’vi characters are played by actors of color, led by a Dominican, Zoe Saldana, as the princess. The film also is an obvious metaphor for how European settlers in America wiped out the Indians.

Robinne Lee, an actress in such recent films as Seven Pounds and Hotel for Dogs, said that Avatar was “beautiful” and that she understood the economic logic of casting a white lead if most of the audience is white.

But she said the film, which remained No. 1 at the box office domestically for the fourth straight weekend with $48.5 million and is second among all-time top-grossing films worldwide, still reminded her of Hollywood’s “Pocahontas” story — “the Indian woman leads the white man into the wilderness, and he learns the way of the people and becomes the savior.”

“It’s really upsetting in many ways,” said Lee, who is black with Jamaican and Chinese ancestry. “It would be nice if we could save ourselves.”

Annalee Newitz, editor-in-chief of the sci-fi Website io9.com, likened Avatar to the recent film District 9, in which a white man accidentally becomes an alien and then helps save the aliens, and Dune (1984) in which a white man becomes an alien Messiah.

“Main white characters realise that they are complicit in a system which is destroying aliens, aka people of color ... (then) go beyond assimilation and become leaders of the people they once oppressed,” wrote Newitz, who is white. “When will whites stop making these movies and start thinking about race in a new way?”

Black film professor and author Donald Bogle said he can understand why people would be troubled by Avatar although he praised it as a “stunning” work.

“A segment of the audience is carrying in the back of its head some sense of movie history,” said Bogle, author of Toms, Coons, Mulattoes, Mammies & Bucks: An Interpretive History of Blacks in American Films.

Bogle stopped short, however, of calling the movie racist.

‘We should respect other races — humans or otherwise’

Writer/director Cameron, who is white, said in an email to The Associated Press that his film “asks us to open our eyes and truly see others, respecting them even though they are different, in the hope that we may find a way to prevent conflict and live more harmoniously on this world. I hardly think that is a racist message.”

There are many ways to interpret the art that is Avatar.

What does it mean that in the final, sequel-begging scene, Sully abandons his human body and transforms into one of the Na’vi? Is Saldana’s Na’vi character the real heroine because she, not Sully, kills the arch-villain? Does it matter that many conservatives are riled by what they call liberal, environmental and antimilitary messages?

Is Cameron actually exposing the historical evils of white colonisers? Does the existence of an alien species expose the reality that all humans are actually one race?

Although the Avatar debate springs from Hollywood’s historical difficulties with race, Will Smith recently saved the planet in I Am Legend and Denzel Washington appears ready to do the same in the forthcoming Book of Eli.

Bogle, the film historian, said that he was glad Cameron made the film and that it made people think about race.

“Maybe there is something he does want to say and put across” about race, Bogle said. “Maybe if he had a black hero in there, that point would have been even stronger.”