Switzerland's first drive-in "sex boxes", which opened in Zurich to tackle illegal prostitution, are being hailed as a success by officials.
"After two months I can say that this guarded prostitution site is working," AFP cited Michael Herzig, director of social services for sex workers in the city, as saying.
Despite being perceived as a clean and conservative-minded city, Zurich has a burgeoning red light district. The city has struggled to fight gangs, particularly from Eastern Europe who traffic women.
The "sex boxes" equipped with an alarm button, security guards and safe sex posters, are the latest attempt to control Zurich's prostitution industry.
Customers can drive up to the sex workers, negotiate a rate, and then park in one of the garage-like boxes to have sex.
(Read more: Zurich turns to drive-in 'sex boxes' for prostitutes)
"We did not have any major problems, such as with pimps, violence or the neighborhood," Herzig said, adding that he was surprised things had gone so smoothly.
An average of 14 sex workers have used the site each day since it opened, he said. While the number was less than half of the amount of women working in Zurich's notorious red-light district, the figures show that prostitutes are welcoming the new system, Herzig said.
Sex workers have to pay $43 a year to use the facilities as well as $5.40 a night in tax to use the facility. Prostitution is legal in Switzerland, providing women have health insurance and are registered with the authorities.
Around 100 prostitutes are believed to work on the streets of Zurich, out of a total of 1,200 officially registered with the city. Others work in massage parlors and bars.
(Read more: Dirty money: The business of high-end prostitution)
Voters approved the $2.6 million project in a referendum last year.
But there are doubts over whether the scheme is as successful as the city makes out.
"Some women can't or don't want to work in this place. This situation in our opinion is not as good as the government says it is," Regula Rother who runs a drop-in center for prostitutes, told CNBC.
"They are also going to close many of the little saloons (parlors) where many other prostitutes work. Many are going to lose their jobs and we don't know where they going. I think some of them will be pushed into working illegally."
—By CNBC's Arjun Kharpal: Follow him on Twitter @ArjunKharpal