As many as one-in-three lung cancer patients visit their GP multiple times before eventually presenting to emergency, acutely unwell, prior to their diagnosis, a Cancer Council NSW study has found.

Researchers say the findings highlight the urgent need for more research into the early detection of the complex disease.

Using data from the Sax Institute's 45 and Up Study, the study included 647 newly-diagnosed non-small cell lung cancer (NSCLC) patients, which accounts for more than 80 per cent of all lung cancers.

It found that 35 per cent of patients presented to an emergency department up to one month before or in the month of diagnosis.

Of these, most were ex-smokers and had been diagnosed with advanced stage disease.

The majority (92 per cent) of lung cancer patients had visited their GP at least three times in the six months prior to diagnosis, according to the findings.

Lead researcher Professor Dianne O'Connell from Cancer Council NSW says this suggests patients were not using the emergency department as their primary point of contact but were also using other healthcare channels prior to diagnosis.

"For many lung cancer patients, poor survival is attributable to being diagnosed at an advanced stage," Prof O'Connell noted.

Also of concern, nearly one-in-three patients did not receive any treatment after diagnosis.

Patients without private health insurance or those who were older were less likely to receive treatment, according to the data.

Prof O'Connell says this suggests inequities in lung cancer treatment exist.

"A number of previous studies in the past 20 years have shown this gap - essentially, nothing's changed since 1996 in terms of someone's likelihood of receiving treatment," Prof O'Connell said.

"Future research should address opportunities to diagnose lung cancer earlier and to optimise treatment pathways - regardless of someone's health insurance status," she said.