About 125 hours of footage was shot, most of which was improvisation from the cast. The process of editing that down to a 90-minute movie took almost a year. The directors have stated that they are considering making all the footage available on-line, so that fans can edit their own version.
Stu Rutherford (Stu), had not played a primary acting role in a movie prior to appearing in this one. He was an extra in Boy (2010). Stu was a part-time business analyst for a Wellington company, LanWorx. He was hired for the film under the impression that he would be working on computers, and that he would play a small part in the film.
Jemaine Clement and Taika Waititi wrote 150 pages of script, but chose not to show it to a single person involved in the film (both crew and cast). They only described broad strokes of what each scene was about, sometimes providing a beginning and an end point. This was to keep things spontaneous and to allow the actors to be surprised by the events unfolding before their eyes.
Taika Waititi based his performance on his mother. Jemaine Clement based his on Gary Oldman in Dracula (1992).
The building used for the exterior shots of the vampires' house used to be Peter Jackson's office.