The news comes following the Sydsvenskan newspaper's probe into illegal prostitution among the Thai massage parlours in Malmö, Sweden's third largest city. Local police receive "several tip-offs a week" but do not prioritize the matter, they told the paper.
Of the 25 parlours called in the survey, five offered a "happy ending". There are around 50 parlours in the city.
On Wednesday, one Thai worker spoke out about her frustration at being constantly asked about sex by the customers.
"I am so angry when people ask me about 'happy ending'. I work hard and I'm proud of my profession," Pornpinum Meejaii said.
But this was evidently not the case throughout the other centres around Malmö.
"We can do happy, happy endings. Come in and see," one masseuse told the paper, but refused to discuss on the phone how much it would cost.
On different online fora, customers share information about the best places in the city, with one stating that a 30-minute massage with a happy ending set him back 700 kronor ($107).
When the newspaper visited the parlours, each of the staff workers denied that they ever offered sex.