"Even at one of the top hotels in New Zealand, my colleagues get requests for extra services from hotel guests," she said.
"But the funny thing is, the requests are usually made to therapists who are Asian."
Chia said some Chinese and Thai massage shops had tainted the sector and many New Zealanders now associated oriental massage and massage therapists with sex.
At Jula Thai Massage in Kingsland, owner Oubonwan Tan has a sign warning customers that any form of sexual harassment will not be tolerated.
"We only provide Thai massage treatment, it does not involve any sexual activities," the sign reads.
"We reserve the right to ask you to leave or to have you removed if you in breach to our staff (sic)."
Tan, who had worked at several other Thai massage centres - including one that had been closed down following a Labour Inspectorate investigation - said therapists were often propositioned for sex acts.
Family First New Zealand is calling for a critical review of the 2003 Prostitution Reform Act and is opposed to calls to allow international students and other temporary migrants to work legally in the commercial sex industry.
"Allowing migrants on student visa or work visa to work as prostitutes will simply open up a huge market for trafficking and exploitation which, based on anecdotal evidence, is already happening," said spokesman Bob McCoskrie.
"More and more vulnerable people are becoming victims because of the flawed decriminalisation of prostitution."
McCoskrie said a government report on prostitution after decriminalisation found that street workers experienced up to three times more violence than other workers including rape, holding against will and physical violence - which were reported less than 20 per cent of the time.
"How can we be serious about reducing sexual violence against women when the state legitimises the sexual abuse and exploitation of vulnerable people," he said.
"There is a healthy stigma against prostitution, and for good reason."
Debbie Wiesehan, manager of Streetreach, said she would hate for New Zealand to be known as a place where women could come to work in prostitution.
Wiesehan said many migrant sex workers feared authorities and weren't reporting exploitation because they were afraid of their minder or immigration status.