A woman allegedly forced into sexual servitude has told a court she was "scolded" for not performing a sex act and worked 17-hour days at a Sydney brothel.

Chee Mei Wong "coached" the woman on what sex acts to perform and chastised her after a customer complained about her refusal to perform a certain act, the District Court in Sydney heard on Wednesday.

Wong, 37, has pleaded not guilty to conducting a business involving the sexual servitude of other people and six counts of employing and exploiting non-citizens in breach of their visas.

The crown has alleged Wong, also known as "Yoko", ran the Diamonds brothel in Willoughby in Sydney's north between 2008 and 2010.

The court heard she employed six women of Indian background who were recruited in Malaysia and sent to Australia on student visas.

The women spoke little or no English and were told they would have to work until they paid off the cost of their airfare, visa and course fees - amounting to a debt of about $5000.

The court heard one of the of the women, identified only as Witness B for legal reasons, arrived in Sydney from Malaysia with a friend in December 2008 after an agent called "Johnny" organised a passport, visa and airline ticket.

She said she had thought she was coming to Australia to study but discovered she would be working in the sex industry.

The women stayed in a unit with mattresses on the floor and were introduced to a woman called Yoko on their first day there.

Witness B said Yoko asked her if she had any "sexy clothes" before she asked her to lift her top and inspected her body.

"She looked at my tummy and looked at my body as to how it was shaped," she said.

The court heard Yoko demonstrated an act the woman was expected to perform using ice cubes and tea and told her to perform oral sex without condoms and other acts, including licking.

"She said you have to do this without failure, only then will you have a lot of customers," the woman told the court through an interpreter.

"I told her I'm not used to all this. I'm not familiar with all this. I won't be able to do this," the woman said.

The woman said Yoko told her, "If a person asks, you have to do this."

After a customer complained about the woman's failure to carry out the act, the woman said Yoko scolded her in a "high, raised voice".

"She scolded me very badly," the woman told the court. "She used very bad words."

She said Yoko told her, "I'm the person who is in charge of this place."

The woman said she worked 17-hour days from 11am to 4am, was fined $10 if she was late and couldn't leave the brothel without permission during working hours.

She said when she worked in the sex industry in Malaysia she could choose her own clients and working hours, and did not have to perform any acts she did not want to.

Wong's defence barrister, Bruce Quinn, has previously told the court Wong is a "woman of good character" who only worked at the brothel as a casual receptionist.

The trial continues before Judge Deborah Sweeney.