A test screening for the film was held in which a lot of the audience walked out before it even ended.
While overshadowed by the popularity of the DC comic character Swamp Thing, it was actually Marvel's Man-Thing that debuted first in May 1971. Marvel considered taking legal action against DC but this was dismissed probably due to the fact that both Man-Thing and Swamp Thing were derivative of Hillman Periodicals' The Heap. This swamp superhero first appeared in 1942.
Although filming was originally intended to be done in New Orleans, budget realities forced the production to be relocated to Australia. They were the first production to use the new Kurnell studios, and enlisted regional actors for virtually every role.
The coroner Val Mayerik (Brett Leonard) who is played by the director is a reference to the comic artist by the same name. Val Mayerik drew early issues of the official Man-Thing comic book as well as earlier appearances of Man-Thing in Fear comic books in the early 1970s.
The film's budget was 5 million dollars, not including marketing. The film earned a worldwide total of $1.1 million.