The woman was receiving treatment for lower back and groin pain when Riaz Behi asked her to remove her underwear and began massaging her legs, groin and buttocks, the NSW District Court heard on Monday.

Dazed from a night of poor sleep, the woman recalled feeling one of Behi's fingers go inside her.

"I felt it, I was shocked and then my body reacted in a jumping manner," the woman, through an interpreter, told the jury in Darlinghurst.

"I did not want to have this kind of experience but I didn't know what to say to Behi."

Behi, 45, has pleaded not guilty to five counts of aggravated sexual assault and eight counts of aggravated sexual touching, with his lawyer suggesting the incidents during 10 consultations from January to April 2019 never occurred.

The woman said the assault on February 7 only occurred for a second, at most.

She couldn't recall what occurred next in the consultation but remembered asking herself over and over what was going on.

The woman became tearful when explaining his treatment away from her genitals was making her feel better and that she'd begun to believe she should not doubt "a doctor" and his treatments.

She said she had been "shocked" at the start of an earlier consultation when Behi instructed her it was "necessary for my treatment" to remove clothes and underpants.

But her friend, who paid for the consultations with the chiropractor, addressed her concerns by questioning why she didn't trust Behi.

"In my understanding, (he said) something like 'Behi is a medical doctor and he has good reviews, why don't you trust him?'" she said.

The Crown alleges Behi's assaults included episodes of digital penetration and oral sex.

The trial has heard the woman mostly communicated with Behi and her friend through Google Translate.

"In Japan, removing pants never happened for the purpose of massaging - absolutely never happened," the woman said.

"But, in Australia, I thought it was common to remove my underpants for the purposes of treatment so I didn't pay much attention to it."

The chiropractor agrees none of the touching alleged by the woman constitutes appropriate chiropractic treatment.

The jury has been told a live issue will be why the woman kept returning for treatment if such "horrendous things" were happening.

"No one in the circumstances outlined by the Crown would dare be putting up with that kind of treatment," Behi's barrister, William Brewer, has told the jury.

Mr Brewer says his client has never had a personal or professional complaint against him in 18 years of practice.

The trial resumes on Tuesday.

Australian Associated Press