Why men rape

She has interviewed hundreds of rapists across the globe and heard tales of a kind of horror that makes the blood boil.

South African professor Rachel Jewkes believes the only way to break the cycle of sexual violence against women is to understand why it happens in the first place.

"The reasons why men rape in South Africa are the same reasons they rape here and the most common statements really amount to notions of sexual entitlement," she said.

Professor Jewkes, the director of one of the largest sexual violence research centres in the world, is in Melbourne as a guest of the Victorian Institute of Forensic Medicine to speak at its biennial oration on Thursday night and will also meet with the federal government to talk policy.

"We haven't got perpetration research from Australia, this is something that is emerging in the last few days of conversation, it's definitely one of the gaps," she said.

That gap was alarming in post-apartheid South Africa when she uncovered the prevalence of rape in what was supposed to be research into teenage pregnancy in 1995.

"We interviewed 24 of them and 23 of them told us stories of basically rape and violence from partners," Professor Jewkes said.

That spawned interviews with perpetrators in South Africa, Papua New Guinea, Indonesia and Bangladesh.

It is a field difficult to view without emotion, and questions like "Have you ever slapped a woman?" and "Have you ever choked or burnt or pushed a woman?" avoided words like "violence" and "abuse".

Most of the almost 11,000 men interviewed were done by way of questionnaire and anonymously in order to extract information that aimed to one day prevent crimes happening in the first place.

"It's actually much easier than you'd ever imagine to get men to tell you about violence," Professor Jewkes said.

"There are a lot of men who are violent towards women who, from their framework, feel what they did was justified."

Responses like "I wanted to have sex so I made her have sex with me" were common.

"It comes from our society and from ideas around masculinity," Professor Jewkes said.

"The assumption in many societies is that women should come under men's control so when a man decrees he wants something like sex he can go and have it."

There are days she has blinding anger and heartbreak, particularly when she hears a young women's first foothold into a relationship is an experience of violence and appalling control.

"The thing that keeps you going when you work in the field is a sense that the world can be different, that you can make it different, that you can stop these things from happening," she said.

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