The film, titled "Daddio" and starring Dakota Johnson and Sean Penn, was broadcast to the entire cabin after technical issues prevented passengers from selecting individual movies, as reported by NBC News.
The R-rated movie, which contains profanity, sexual content, and brief nudity, played for nearly an hour and could not be paused, dimmed or shut off, The New York Times reported, citing online comments made by a passenger who reported being on the flight.
"It was super uncomfortable for everyone, especially with families and kids onboard," the person said.
Qantas has apologized for the incident, saying the movie was not appropriate to play for every passengers on board and a family-friendly movie was later aired for the rest of the flight.
"We sincerely apologize to customers for this experience," it said in a statement quoted by The Guardian, adding that it was looking into how the movie was selected.