Cameron said nobody is more disappointed than he, but he's buoyed by the extraordinary work Weta Digital is doing to bring the world of Pandora to life.
The Hollywood heavyweight was among more than 50 Avatar crew granted permission to arrive in New Zealand in May to resume work on the $1 billion movie sequels.
The film crew had touched down in Wellington through a little-known loophole that allows foreigners through our closed borders.
Economic Development Minister Phil Twyford revealed there was a category for border exemptions for foreigners deemed essential to a project of "significant economic value".
The film industry said allowing key film personnel, like producers and cast, into New Zealand would be "huge" as it could trigger thousands of jobs for Kiwis.
Oscar-winning producer, Jon Landau, spoke on the the film crew's arrival almost two months ago.
"Made it to New Zealand," he posted on Facebook.
"Our 14-day Government-supervised self-isolation now begins."
He announced he would be returning to New Zealand to resume production on the sequel, telling RNZ the crew felt "very comfortable" to be "coming to the safest place in the world".
"We feel very comfortable because of the actions of your Government and also the responsibility the people took to really curb the virus there.
"So we feel we're coming back to the safest place in the world possible, thanks to a team of people that we've worked with. We believe we have a very thoughtful, detailed and diligent safety plan that will keep everybody as safe as possible in these unprecedented times."
Landau said "far fewer people" than they had last year would be flying into New Zealand and only those deemed "essential" to the production would enter the country.