E Jean Carroll has been an advice columnist for decades and she has some advice for women who are thinking of speaking out about sexual harassment or assaults.

Key points: E Jean Carroll alleges Donald Trump assaulted her in a department store change room

E Jean Carroll alleges Donald Trump assaulted her in a department store change room Donald Trump denies that the incident took place

Donald Trump denies that the incident took place Ms Carroll says the younger generation of women is forcing cultural change

"No woman should be scared of coming forward," she told 7.30.

"Because in two days everyone will have forgotten and moved on."

Carroll recently went public about an alleged incident involving the current President of the United States in a dressing room at a New York department store in the early 1990s.

"It's an astonishing thing that people have already tried to forget it, because they feel helpless to do anything about it," she said.

'It hurt and it was against my will'

E Jean Carroll on the cover of New York Magazine. ( Supplied: New York Magazine )

In her book, What Do We Need Men For?, Carroll said she had a chance meeting with Donald Trump at New York department store Bergdorf Goodman, which ended with her being pinned to a change room wall with Mr Trump forcing himself on her.

"The minute that the door closed it was a dangerous situation," she said.

"It was a horrible, violent scene.

"It hurt and it was against my will."

But she insisted the incident did not ruin her life.

"It didn't even destroy a portion of my life, it destroyed a day in my life. But I got out of it quickly and moved on," she said.

Mr Trump has denied the allegations and said the incident never took place.

"I have no idea who this woman is," Mr Trump said.

"It is a totally false accusation."

In a statement, Mr Trump called the accusation "fake news" and said there was no evidence.

"No pictures? No surveillance? No video? No reports? No sales attendants around — I would like to thank Bergdorf Goodman for confirming they have no video footage of any such incident, because it never happened," he said.

It was only after Mr Trump was elected president and more than a dozen women had come forward alleging inappropriate behaviour that Carroll began to think about what had happened to her and decided to catalogue what she calls "the hideous men" in her life.

She nearly did not include Mr Trump on the list — and only ranks him 20th out of 21.

Challenging powerful men

Donald Trump has been accused of inappropriate behaviour by more than a dozen women. ( Reuters: Leah Millis )

But Carroll had noticed a strange phenomenon.

"The more that women came forward and told their stories, the more popular [Mr Trump] became," she said.

"In this country, voters were attracted by the fact that he could take whatever woman he wanted.

"So I stayed quiet."

She said Mr Trump was one of a long line of powerful men who had used that power to take advantage of women.

"We know they could have any woman they wanted, they did take whatever women they wanted," Carroll said.

"Donald Trump is the essence of that.

"He believed that women were there for his taking — and that's what he did."

But how do you challenge that behaviour?

"It took 40 years to bring Bill Cosby to acknowledge what happened and send him to jail. Forty years," Carroll said.

"He had lawsuits in 10 different states.

"And so, it is very difficult to stop a powerful man.

"Donald Trump has, what, 200, 300 lawyers? It is almost impossible.

"He denies everything ... then he turns it around and attacks the woman."

Why come forward now?

E Jean Carroll on The Ask E Jean Show in the mid-1990s. ( Supplied: Pan Macmillan Australia )

Carroll said it took letters from her readers to make her realise she needed to speak out.

"There's so much to learn because these women are pouring their hearts into these letters," she said.

"They're asking me for advice.

"Basically, that's why I came forward.

"They've been asking me, should they report their boss? Should they call the police when their husband beats up their dog?

"And there I am advising on what to do and I have not come forward.

"So I just say, 'It's time to do it'."

Carroll said she belonged to the "silent generation" who responded to unwanted advances with a slap and then shrugged it off.

"You know what, that did not work," she said.

"That did not change anything. We didn't change the culture.

"The young women today, they're actually changing the culture of sexual violence in this country.

"I love it. I love what they're doing."