Patients with a high suspicion of cancer could take 20 days from referral to diagnosis.
"What we found was that one-third of our patients didn't have cancer and they could be given that news on the same day as their appointment which immediately relieved an enormous amount of anxiety," respiratory physician Dr Stephen Iles said.
"For those people who were diagnosed with lung cancer, we were able to determine a pathway of treatment as soon as possible."
Lung cancer causes more deaths in New Zealand than other cancers - more than 1600 people dying a year.
"Clearly we are still very focused on preventing lung cancer which means eliminating smoking, however, given lung cancer is the number one cancer killer for men and women the sooner we can diagnose it the better," Dr Iles said.
"If you have a persistent cough for a month or so you are well advised to go and see your GP as soon as possible."