Peter Jackson is in a stable condition in the intensive care unit of Wellington Hospital in Wellington, New Zealand, after surgery for a perforated ulcer.
Publicist Melissa Booth said the Lord Of The Rings director was "doing well" but would be in the hospital for at least a few more days.
She said doctors expect the filmmaker to make a full recovery.
Jackson was admitted to Wellington Hospital last Wednesday after complaining of acute stomach pains.
His illness has delayed the start of filming of The Hobbit, the two-part prequel to his Academy Award-winning Lord of the Rings trilogy.
Production of The Hobbit had previously been troubled by financial issues and the departure of its initial director Guillermo del Toro.
© Press Association