MUMBAI: James Cameron's highly anticipated sequel to Avatar has been delayed.

Earlier, the makers had planned to bring Avatar 2 in December 2014 followed by Avatar 3 next year but producer Jon Landau has confirmed that bringing back-to-back sequels would not be possible, it is understood.

"We're not naming dates, but I think 2014 will be a tough date for us to make. It's about getting it right... movies make release dates; release dates don't make movies," that producer has reportedly said.

Cameron spent a lot of time and research on his recent dive to the bottom of the Mariana Trench and he was also involved in the 3D conversion of Titanic, which is said to be the cause of the delay.

It is said that Landau had already started work on the sequels with his core team including New Zealand effects company Weta Digital that is developing an underwater motion capture system that will help Cameron explore the oceans on Pandora.