Moran, who was in her mid-50s, was unable to attend the world premiere of The Hobbit movie in New Zealand last week because she was in hospital, but no information is yet known about her cause of death.
The producer had teamed up with Jackson several times in the past, on films including King Kong and The Lord of the Rings trilogy, and she also worked on James Cameron's Avatar.
Cameron said: "Eileen was an integral part of building Weta Digital into the most powerful engine for imaginative imagery that ever existed, and she shepherded some of the milestone films of her generation to completion."
Moran served as leader on the Weta Digital team that won the Best Visual Effects Oscar for sci-fi blockbuster Avatar in 2009, and she won an award from the Visual Effects Society for her work on King Kong, as well as two more for Avatar. In 2011, she was nominated for Steven Spielberg's The Adventures of Tintin.
She also worked on movies such as Fight Club, I, Robot, X-Men: The Last Stand, The Chronicles of Narnia: Prince Caspian, The Lovely Bones and this year's Prometheus.
Moran is survived by her children, Jack and Ava.
- WENN