Security guards employed by Roadshow Film Distributors collected cellphones from patrons in the foyer of both Hoyts and Rialto.
They were returned after the movie.
Rialto cinema manager Craig Robinson said the move was a precaution to stop the film being recorded by a patron using a phone camera and posted on the internet.
"It's a national standard for advance screenings like this when there's a worldwide release the next day."
Mr Robinson said similar security measures had previously been employed at the theatre.
"You'll find it happens at all the major locations around the country.
"There's a lot of these Valentine's Day screenings happening and it will be the same for them all."
Mr Robinson said movie piracy was not "a major problem" in New Zealand and he had not encountered a situation where a patron in his theatre had tried to use a camera to record a movie.
"Obviously, you don't want to be the first one.
"There's a lot of money and promotion and time gone into movies like this, so you don't want to be the site where something happens."
Hoyts location manager Darryl McLeod said the security measures had been in place "for years" in Auckland and had finally started in Dunedin.
"It is obviously to do with piracy, which we have a huge problem with both nationally and internationally.
"It costs the movie industry millions and millions of dollars."
