The studios warning followed a decision by the Motion Picture Association of America (MPAA) to impose an "R" rating on "The Great Raid," the story of the liberation of a World War II Japanese concentration camp in the Philippines by US soldiers.
The rating, imposed for "strong war violence and brief language," means that youngsters under the age of 17 are not allowed to witness "a momentous event in US history" unless accompanied by an adult, Miramax said.
"There have been a number of war films with comparable levels of violence that were given a PG-13 rating including such films as Hotel Rwanda, Master and Commander and Pearl Harbor," said outgoing Miramax boss Harvey Weinstein.
"The Great Raid tells the true story of what happened to our soldiers, many of whom were still teenagers, who were sent overseas during World War II. The violence is not there to shock the audience, rather, its to show them an accurate depiction of what happened, and is by no means excessive," he said.
"The Great Raid" is based on the real-life rescue by American troops in 1945 of 500 prisoners of war held by Japan in the Cabanatuan concentration camp in the Philippines.
The movie, starring Benjamin Bratt, is due for release in North America on Aug. 12. It also stars Filipino actor Cesar Montano.
Restrictions of ratings, especially in the busy summer season when schoolchildren are on holiday, can seriously hurt a movies box office performance by limiting the ticket receipt potential.
"The only way to capitalize on the historical importance of the film is to make it accessible to young people, which will only be successful if the MPAA allows us to reach them," fumed the movies director John Dahl.
The MPAA, the powerful lobby group of the major Hollywood studios, came up with the ratings system in 1968 after agreeing to police movie content in return for the abolition of the US government censors board.
Miramax is a unit of the Walt Disney Co., which is ironically one of the members of the MPAA.
Miramax founders Harvey and Bob Weinstein are due to leave the company they created for their new movie production house on Sept. 30 after they failed to agree to terms with Disney on the renewal of their contracts.