Environmental factors could be behind New Zealand's high rate of breast cancer.

Researchers from Auckland University tested tumours from women undergoing treatment here and from other countries.

They found there were no genetic differences, effectively meaning it could be a result of lifestyle habits.

Eight Kiwi women are diagnosed with breast cancer every day, higher than the rate in Australia and the UK

Professor Andrew Shelling said the research shows there needs to be better tools for detection.

"When know that screening rates in New Zealand, especially Maori and Pacific women, are lower. Obviously more work needs to go into that sort of area and try to encourage women to detect it and get picked up earlier," he said.

Early detection will be helped by the new Government, which has promised to increase the age of free screenings from 69 to 74.

Breast Cancer Foundation researcher Adèle Gautier said women are far more likely to get the disease in their 70s.

"Woman from age 70 to 74 who develop breast cancer, if that cancer was found on a mammogram they have a 57 per cent lower chance of dying of breast cancer so that's huge," she said.

Gautier said the cost of mammograms of about $250, which is out of reach for many older Kiwis.

October is Breast Cancer Awareness Month.