The sequel to the hit 2009 sci-fi blockbuster has been in production for years, with its scheduled release date pushed back eight times.
Cameron also disclosed that filming was nearly complete for Avatar 3, the second of four planned Avatar sequels.
Talking to Arnold Schwarzenegger in a video call ahead of the 2020 Austrian World Summit environmental conference, Cameron stated that filming on Avatar 2 was “100 per cent complete”.
“Covid hit us like it hit everybody... We lost about four and a half months of production,” he said.
“As a result of that, we've rolled around one more full year for a release in December of 2022. That's been announced already,” Cameron explained. “Now that doesn't mean I have an extra year to finish the film, because the day we deliver Avatar 2 we'll just start working on finishing Avatar 3.”
The original Avatar starred Sam Worthington, Zoe Saldana and Sigourney Weaver, and told the story of the Na’vi, a tribe of blue-skinned aliens into which Worthington’s human marine Jake Sully ingratiates himself.
The film smashed box office records, becoming the first film to gross more than $2bn. While it was overtaken by Avengers: Endgame in 2019, it held the distinction of being the highest-grossing film of all time for nearly a decade.
“So where we are right now,” Cameron said, “I'm down in New Zealand shooting. We're shooting the remainder of the live action. We've got about 10 per cent left to go.
“We're 100 per cent complete on Avatar 2 and we're sort of 95 per cent complete on Avatar 3.”
Avatar 2 is scheduled to come out in cinemas in December 2022.