The 'Avatar' sequel is being delayed.

The eagerly anticipated follow-up to James Cameron's sci-fi film - starring Zoe Saldana, Sam Worthington and Michelle Rodriguez - was expected to be released in late 2013, but producer Jon Landau has now claimed it has been delayed for around two years.

Speaking to Bleeding Cool, he said the project was "four years away".

Two sequels are planned to the movie - the highest grossing film of all time, earning $2.7 billion worldwide - so with the first now thought to arrive in late 2015, early 2016, the third picture could be released as late as 2017.

Speaking last year, James claimed he was writing the scripts for the follow-ups.

He said: "I am in the process of writing the next two 'Avatar' films now. We are planning to shoot them together and post them together, and we will probably release them not quite back to back, but about a year apart. Christmas 2014 and 2015 is the current plan."

It is believed the two sequels will change from the setting of the first film on the planet of Pandora to from the land to its oceans.