Men who smoke are up to 40 percent more likely to suffer from impotence than those who don't," said Dr Christopher Millett, of Imperial College London, who worked on the research.

He added that the more cigarettes smoked, the greater the risk of suffering from a sexual performance problem. But even men who smoked less than 20 cigarettes a day, had a 24 percent raised risk of impotence.

"It is not just older men who suffer from impotence, younger men are also affected as well," Millett added in an interview.

The findings, reported on Thursday in the journal Tobacco Control, are based on a survey of 8,000 men in Australia aged between 16 and 59 who took part in a study of health and relationships.

Almost one in 10 reported an impotence problem lasting more than a month during the previous year.

About a quarter were smokers and more than 6 percent said they got through over 20 cigarettes a day.

Men who smoked more than a pack or more a day were 39 percent more likely to report sexual problems, according to the study.

"For decades, cigarettes were marketed as symbol of virility, as in the macho Marlboro Man ads," said Deborah Arnott, of the anti-smoking group ASH (Action on Smoking and Health).

"Yet the reality is that smoking is a primary cause of impotence which may also be an early indicator of coronary heart disease," she added in a statement.

Research has shown that smoking is a leading cause of preventable death. It increases the risk of heart attack and stroke, respiratory problems, lung and other types of cancer.

Millett said if young men want to avoid the embarrassment and distress of impotence they should not smoke.

"By highlighting this link between smoking and erectile problems, we may be able to motivate these men to quit," he added.