A study in Australia is suggesting many cancers are over-diagnosed and over-treated, but that may not be the case here. 

Published in the Australian Medical Journal, it suggests roughly 18 per cent of cancers are over-diagnosed, which leads to treatments that causes further health problems. 

But New Zealand Cancer Society Medical Director Chris Jackson says that the study is creating an awful lot of hype. 

He says that there are some treatments that find pre-cancerous lesions that have a small chance of leading to prostate and breast cancer. 

"I think the study has unhelpfully basketed together pre-cancerous lesions with cancerous lesions." 

He told Mike Hosking that New Zealand might not be in the same boat.

"In New Zealand, we've got the opposite problem - that is, that we don't have enough access to early diagnosis, and we know far too many New Zealanders die prematurely of cancer."

He says that there are some treatments that find pre-cancerous lesions that have a small chance of leading to prostate and breast cancer.