Seventy per cent of American adults would support an R or Restricted rating for movies that show smoking, a new survey suggests.

The survey of 1,800 Americans by the American Medical Association AMA Alliance, an arm of the AMA, shows public concern over the issue of tobacco imagery on screen has grown substantially.

The AMA has been engaged in a debate with movie studios over the depiction of smoking on screen, especially in films that might appeal to 10-14-year-olds, the age at which many young people begin to smoke.

"An overwhelming majority of adults, parents, believe that teens are more likely to smoke if they see smoking in movies," Robert McMillen, author of the report, said in an interview with CBC Television.

About 81 per cent of the parents surveyed agreed that seeing actors smoking was an enticement to smoke for young people.

"There should be no smoking in movies that are rated PG or PG-13 unless the story shows harmful consequences of smoking," said McMillen, a researcher at Mississippi State University.

He is also recommending an R rating for any film that shows smoking. And he wants full disclosure when filmmakers received funds from the tobacco industry.

More than 60 per cent of adults wanted tobacco branding out of all movie scenes and two-thirds of adults wanted movie theatres to show anti-tobacco spots before any film with tobacco images, the survey shows.

The AMA Alliance is stepping up its Smoke Out campaign, which urges the Motion Picture Association of American and movie studios to voluntarily take steps to reduce youth's exposure to movie smoking.

It had a series of meetings with movie studios last year on the issue.

"The movie industry said it wanted to know what parents think," McMillen said.

"There is an overwhelming and consistent body of evidence that shows a clear link between smoking in movies and youth starting to smoke," McMillen said.

"This national survey demonstrates substantial public and parental support for voluntary policy changes by Hollywood to reduce this toll, including [an] R rating for almost all future tobacco scenes."