At 5pm on Monday, she got the phone call from NSW Attorney-General Mark Speakman she'd spent more than two years fighting for.

Within 20 hours, she was standing next to Mr Speakman as he announced a historic overhaul of sexual consent laws in NSW.

That reform was thanks to Ms Mullins' "incredible courage", Mr Speakman told reporters.

In 2018, she told her story of a horrific sexual encounter in 2013 in a Kings Cross laneway on the ABC's Four Corners program.

She spoke about the toll taken on her by the two criminal trials and appeals that followed in the next four years and ended in the accused, Luke Lazarus, walking free.

Mr Speakman referred a review of the state's consent laws to the law reform commission the day after the story aired.

Since then, 26-year-old Ms Mullins has been advocating alongside other survivors and experts for the state to adopt the so-called "affirmative consent" model.

Affirmative consent means a person needs to take steps - with words or actions - to ascertain consent from their sexual partners.

And it means a person does not consent to sexual activity until they say or do something to communicate it.

She describes it as the "fundamental issue" with Australia's consent laws.

Ms Mullins was disappointed when the law reform commission stopped short of recommending it when it produced its 270-page report last September.

Along with opposition from the NSW Bar Association, she believed it would stop her campaign from succeeding, she said on Tuesday.

"Are they really going to stray from these recommendations that they spent a few years on, even though it's the wrong outcome?" she said.

But Mr Speakman told her in the phone call on Monday afternoon that the government would be taking up all the commission's recommendations.

Then he said they'd be taking one of them further - and introducing a requirement of affirmative consent.

She was "very surprised", she said.

"They actually listened to the voices of the people who know best, the survivors and academics," she said.

She was emotional as she addressed reporters on Tuesday.

"It's a really amazing day that we've all waited a really long time for," she said. "I'm really proud of all the work we did to get here."

Mr Speakman said on Tuesday he wanted to make sure that not only could people like Ms Mullins fight for justice in the courts.

"My determination is to make sure that a case like that never arises again," he said.

His hope is that a change to the criminal law will affect community behaviour, and encourage people to actively seek consent.

In 2017, Ms Mullins walked out of the Supreme Court after learning that Mr Lazarus would not be found guilty of her sexual assault feeling lost and alone, she said.

"I just didn't know what there was left to do. I'd spent so long fighting for that ... I was just like, this system is so totally broken. I don't know how anyone could get through it," she said.

On Tuesday, she had a "weirdly similar feeling" - but for an entirely different reason.

"I'm still left feeling like, what am I supposed to do now? But in a better way."

Another fight was over - and this time she'd won.

Australian Associated Press