Stubbing out smoking in films aimed at teenagers could help slash the rate of tobacco use by up to 18%, according to a study published in the journal Pediatrics.

Cinematic smoking is a potent risk factor for teenagers, with every 500 smoking shots increasing the likelihood of trying a cigarette by up to 49%.

Top grossing films such as Iron Man, Mission Impossible 2, Men In Black and 101 Dalmatians were among the hits watched by the 6,500 children in the study

"Hollywood plays a role by making smoking look really good," the Daily Telegraph quoted lead researcher James Sargent, of the Norris Cotton Cancer Centre, as saying

"By eliminating smoking in movies marketed to youth (it would) lower adolescent smoking by as much as one-fifth," he noted

Though researchers urged smoke-heavy flicks be given a higher classification rating, they say parents also needed to help steer teens away from danger.

"Authoritative parents" who are "effective in monitoring their children" have a strong track record in lowering tobacco use, the study found

"It is also important to motivate and assist parents in restricting access to these movies, which would further reduce adolescent exposure to onscreen smoking," the researchers wrote.