Author and columnist Nicky Pellegrino has gone public on how she was raped at knifepoint as a young woman - and her attacker was never found.

She says she is speaking out now because so many New Zealand women suffer in silence as rape victims, and there is nothing to be ashamed of.

Pellegrino has written about her traumatic experience in this week's Woman's Weekly, saying she woke in her flat, in a small New Zealand town, to find an intruder on top of her, holding a knife to her face.

She did not know the man - all she remembers is that he had a "shock of curly black hair" - and to this day he has not been caught.

She said the incident was over quickly. "I didn't fight back. Later on, that's what really bothered me, because I'm a tall, strong woman and could have put up a struggle against the man who attacked me."

She had not expected to talk about the rape, until she wrote her new book, Recipe for Life.

The book - about a young woman pushed off course by a single event in her life - was not autobiographical but the first chapter reflected what happened to the author.

"I don't want to be known for being raped because, just like in my book, my life is about lots of other things," Pellegrino writes in the Woman's Weekly.

"It's not all linked to that one horrible event. But I'm aware that one in four women in New Zealand go through a similar experience. How many of them ever talk about it? Very few, it seems. Rape is a crime with invisible victims.

"I hope that by standing up and admitting it happened to me, I might in some way help the other silent survivors.

"And in a way, I feel like I'm fighting back at last."