Yasmin came to New Zealand from China to study English as an international student, and was enticed to work at a massage parlour by a brothel operator who said prostitution was "legal in New Zealand".
But during her first day on the job at a central Auckland parlour, the 30-year-old was caught up in a police raid.
"I was so shocked, because I didn't even realise I was doing anything wrong," Yasmin told the Herald.
Detective Inspector Paul Newman said Yasmin (not her real name) was found when four officers entered the parlour on November 30 last year.
"Officers at the scene had initial concerns for the safety of a female individual and spoke with her to make sure she was safe and okay," Newman said.
He said Yasmin was given an opportunity to fully dress before police spoke with her, out of consideration for her privacy.
"The individual stated to police that she was a sex worker and detailed how much she was paid for her services," Newman said.
"Police also spoke to a male client who had paid money in exchange for her services."
The operator was required by law to produce a certifcate on request, but Newman said no operator was located and no certificate was produced that night.
Yasmin was not arrested and Newman said she chose to leave the premises once police had finished speaking to her and had established the circumstances.
Newman said Immigration NZ was contacted that night "as per standard practice" when police became aware there was an immigration issue.
Immigration NZ assistant general manager Peter Devoy confirmed that Yasmin was served with a deportation liability notice.
Devoy said he could not comment further due to privacy reasons.
Yasmin engaged the services of immigration adviser Tuariki Delamere to fight her case.
She was not aware that the Prostitution Reform Act 2003 stated that only New Zealand citizens and residents could legally work in the sex industry.
"I thought it was legal for all, and I was told that it was legal for me," Yasmin said.
Delamere said migrant sex workers were terrified of police, because back in their home countries they would go to jail if arrested.
He said many were victims who had been deceived and enticed to work at massage parlours by unscrupulous brothel operators.
"It is these so-called employers, who have totally no morals whatsoever, that we should be going after," Delamere said.
Yasmin was fighting deportation and Delamere had written to the police requesting further information.
In the letter, Delamere said Yasmin was not providing commercial sexual services and also denied that she admitted to police that she was providing sex for money.