University of Otago medical graduate Dr Ron Jones made those comments during a bioethics talk about his book Doctors in Denial, which he gave at the university yesterday.
The book is Dr Jones' account of trying to raise the alarm at National Women's Hospital in Auckland.
The experiment is thought to have caused more than 30 deaths and led to many unnecessary cancers.
Dr Jones, now a retired obstetrician and gynaecologist and former clinical professor at Auckland University, published a scientific paper, with two senior colleagues, in 1984 that exposed the truth, and what he termed ''the pretty shocking result'' of Prof Green's experiment.
Dr Jones said that after the paper was published, the denials had continued and, even now, ''a small group at National Women's will not accept what's happened''.
The gathering yesterday was chaired by Otago Bioethics Centre acting head Associate Prof Lynley Anderson, who asked Dr Jones if he would have done anything differently, given what had happened.
''You either tell the truth or you don't. There's no halfway house,'' Dr Jones replied.
''I was the most junior member of a very rigidly hierarchical institution.''
''Should I have run off to The New Zealand Herald? In fact, I didn't.''
He noted that former Otago vice-chancellor and epidemiologist Prof Sir David Skegg had first used the term ''unfortunate experiment'' to describe Prof Green's work.
Dr Jones wrote his book in response to a controversial 2009 retelling by Auckland University academic Linda Bryder which tried to present Prof Green's management of patients as acceptable and progressive.
Dr Jones joined the hospital in Auckland in 1973 as a junior obstetrician and gynaecologist, seven years after the experiment began.
Prof Green was trying to prove that carcinoma in situ of the cervix was not a precursor of cancer, and did not need to be removed.
More than 60 people, including Prof Skegg, attended yesterday's talk.
