LOS ANGELES (Reuters) - Avatar director James Cameron said he still aims to make four sequels to the 2009 science-fiction blockbuster. He is moving ahead with production while regulators review the proposed sale of 21st Century Fox's film studio to Walt Disney.

He is about 100 days into shooting the second and third Avatar instalments under a deal with Fox. If those are successful, he plans to continue with the fourth and fifth movies, which he already has written.

Mr Rupert Murdoch-owned Fox has committed to distributing the next movie in the franchise, but the film studio is in the process of being sold to Disney.

Avatar, the story of a blue, humanoid race on a lush moon known as Pandora, is the highest-grossing movie in history with US$2.8 billion (S$3.7 billion) in global ticket sales.

The second Avatar film is scheduled for release in December 2020.

Cameron described the future Avatar movies as "a generational family saga".

"I found myself as a father of five trying to think about what would an Avatar story be like if it were a family drama... obviously it's a very different genre. It's a very different story, but I got intrigued by that idea.

"So this could be the seeds of utter damnation and doom for the project, or it could be the thing that makes it stand apart and continue to be unique.

"Nobody knows until you make the movie and put it out."