Publicist Melissa Booth says Jackson was admitted to Wellington Hospital the night before suffering from severe stomach pains and is now recovering from surgery.
She said Thursday that Jackson was resting comfortably and is expected to make a full recovery.
Jackson's illness will delay the start of filming for "The Hobbit," the two-part prequel to the "Lord of the Rings" trilogy. The movies are based on the novels by J.R.R. Tolkien.