Bollywood is again in the limelight, but this time for inadvertently encouraging youngsters to smoke, with the World Health Organisation saying three out of four films produced in the last decade had shown stars smoking.

Teenagers who watch Bollywood characters smoke are three times as likely to do so themselves, the WHO said in a first such study on the Indian film industry released on Monday.

The Indian government has said it will legislate later this year to ban smoking in public, the sponsorship of sporting events by tobacco companies and advertisement of tobacco products.

But Ambika Srivastava, who conducted the WHO research, said, "The WHO and countries across the world are looking at bans on tobacco advertising but the (film) industry finds ways of getting around it."

Bollywood produces 800 films a year, which are watched by 15 million people every day. A third of Indian television programming is based on Bollywood movies, which are also widely watched in Pakistan and Bangladesh.

The WHO survey found that 76 per cent of the most popular films produced between 1991 and 2002 showed some form of tobacco use. In 72 per cent of the cases, it was cigarette smoking.

Srivastava found that half of India's leading stars, including Shah Rukh Khan, Vivek Oberoi, Ajay Devgan and Jackie Shroff, had smoked on screen.

If young people see one of their idols light up on screen, they are 16 times more likely to think positively about smoking, the survey found.

"The youth thought it was a very cool thing to do. The implication of that is huge," Srivastava said.

"Earlier, only the villains were shown smoking but now there's a very high percentage of the good guys who also smoke in their films."

The study is part of a new international campaign to cut smoking deaths by targeting the world's film industries.

Similar warnings were issued last year about Hollywood films.

The WHO's World No-Tobacco Day later this year will focus on how the fashion and film industries glamorise cigarettes.

An estimated three million people die every year from tobacco-related causes, a third of them in India. Although several Indian states have banned smoking in public places, enforcement has been difficult.

But the film industry in Mumbai is unlikely to react well to the survey.

Mahesh Bhatt, one of India's leading filmmakers, was quoted in the survey as saying that tobacco companies, not movie stars, were to blame.

"If you feel the Indian star smoking on screen is responsible for the consumption of tobacco on the streets of India and South Asia, why don't you go for the jugular and blow off these tobacco manufacturing companies?" he asked.

"When crime increases, when rape increases, the easiest people to blame are the movie stars. How long can you blame the virtual world for your real problems?"

In most of the developing world, cigarette companies are given a much freer reign to advertise their products than in the West.