Former long-distance running star Allison Roe, a campaigner for complementary healthcare, has spoken out in defence of thermal imaging, a popular but controversial investigation for breast cancer.

Ms Roe has featured in advertisements for Clinical Thermography and is a spokeswoman for the company, a national chain.

It conducts thermal imaging of the breast, a test the company describes as "a screening tool".

She said a call by radiologist Dr Mike Baker for the thermography industry to be shut down was "defamatory and malicious".

"It is also robbing women of their God-given right to be proactive about the health of their breasts," said Ms Roe, a Waitemata District Health Board election candidate.

Dr Baker helped to produce a position statement, released by the Ministry of Health and several cancer and medical groups, which says insufficient evidence exists to support the use of thermography, based on images from an infrared camera, for breast-cancer screening or diagnosis.

The signatories urged women aged between 45 and 69 to use the Government's free screening programme, a system they said was proven to reduce a woman's risk of dying from breast cancer.

They said radiologists and surgeons were increasingly seeing women with cancer who had been falsely reassured by thermography - and others who had been told they had cancer but didn't.

Josie Taylor, 40, from Glenfield on Auckland's North Shore, paid about $175 for thermal imaging. The clinic, by phone, delivered a positive result on the Friday before Queen's Birthday Weekend in June, but this turned out to be a false positive.

She had been told of this possibility but it did not lessen the agony of being unable to get medical advice during the long weekend.

She went to a medical breast-screening clinic and was told the waiting list was two to three weeks long.

"I broke down in their reception area. They took me in straight away for a mammogram and ultrasound - and they all came out fine."

Ms Taylor will not have another thermogram but does not entirely regret the experience - not now that she has had the opportunity to speak publicly to warn other women.

"My message would be: stick to what's been tried and tested."

Clinical Thermography has dismissed the position statement, saying it disregards research that has found that thermal imaging improves breast cancer diagnosis if used alongside clinical examination, mammography and ultrasound scanning.

But Dr Baker said that the thermography studies were small and lacked statistical power.

Breast surgeon Dr Belinda Scott said thermography picked up about 18 per cent of cancers, in contrast to about 85 per cent for mammography in women aged 45 to 70.