A study into what became known as the "unfortunate experiment" at National Women's Hospital has found that women whose treatment was delayed suffered profound harm.
Dr Herbert Green conducted a study between 1965 and 1974 and withheld or delayed the treatment of women who had been diagnosed with cervical carcinoma in situ or a pre-cancerous lesion.
The new analysis of Dr Green's study, which was deemed to be unethical by a judicial inquiry in 1988, was done by a multi-disciplinary team led by Dr Margaret McCredie of the University of Otago.
Dr McCredie says the risk of developing invasive cervical or vaginal cancer was 10 times greater for Dr Green's 127 patients - who were not treated for at least six months - than it was for those who received prompt treatment.
A third of his patients subsequently developed invasive cancer, Dr McCredie says, and eight of them died - so any suggestion that he did no harm to the women, she says, is patently wrong.
She says the risk was extremely low in women who were treated promptly.