James Cameron didn't expect the stars of 'Avatar' to get Oscar nominations.

The director - who broke box office records when the 3-D sci-fi film went on to take $2.7 billion - wasn't expecting the main actors, including Zoe Saldana, Sam Worthington and Sigourney Weaver, to be nominated by the Academy Awards because of the use of computer graphics in the film.

He said: "Typically, young leading men don't get nominated until the 15th time they've done it. Leonardo did not get nominated for 'Titanic'.

"Was Zoe's performance spectacular? Absolutely, but there were many great performances last year. But it is arguable that they would have been nominated if you take the computer generated imagery off the table. Put that back on the table - the CGI part of it - and where the acting community is, they are still low down on the educational curve of what this all means.

"I didn't expect it and I cautioned them not to expect it, so they'd therefore not be disappointed."

However, the 55-year-old filmmaker confesses he would not have made the movie without the use of graphics, as the mythical Na'vi aliens, played by Worthington and Saldana, would not have looked right.

He told Empire magazine: "Here's the thing, if it had been in live action, Zoe Saldana would have been in blue make-up and it would not have had the power. Her eyes would not have been those eyes.

"The blue make-up would have looked terrible. I know - every time I go to a convention or a place where someone decides they're going to be a Na'vi, I'm reminded why we did it the way we did."