An algorithm could one day help identify smokers and ex-smokers at high risk of lung cancer.

A simple algorithm that can predict the likelihood of lung cancer in smokers and ex-smokers could revolutionise screening and help save lives, say Australian researchers.

A study by Cancer Council NSW evaluated the performance of the US-developed prediction tool - called PLCOm2012 - among 100,000 smokers and ex-smokers who were part of the Sax Institute's 45 and Up study.

"We showed that it was able to identify around 70 per cent of lung cancers that occurred among those people within six years," lead researcher Dr Marianne Weber said.

The cancer epidemiologist says it was better at predicting people who would go on to develop lung cancer than the current guidelines.

An estimated that 12,434 new cases of lung cancer will be diagnosed in Australia in 2017. Of those, more than 9000 will die.

So far, identifying smokers or ex-smokers at high risk of this deadly disease has been a challenge, says Dr Weber.

"Smoking is the primary factor that puts people at risk for lung cancer: 80 per cent of lung cancers are in people who were smokers. But screening everyone who has ever smoked a cigarette is not feasible and would potentially cause unnecessary testing, costs, and psychological distress," Dr Weber explained.

"Using our results, we estimate that around 29 per cent of people who have ever smoked may be eligible for screening according to the tool, by the time they are 55 years old."

With more research still needed before such a tool could be rolled-out in clinics, the best way to prevent lung cancer is to quit smoking.

"And if you have been a smoker and you do have persistent symptoms, like a persistent cough or sudden weight loss, then we really do urge you to get it checked out by your doctor, " advised Dr Weber.

The Cancer Council NSW study is published in the International Journal of Cancer.