“My store is 100 percent, very clean,” said Shirley Xu, a Chinese immigrant who operates Shirley Day Spa at Fifth Avenue near 78th Street, which has been in business for four years, making it among the oldest of the neighborhood’s spas. “If customers call and ask for bad things, we say no and hang up the phone. ‘Not here, I’m sorry.’ We don’t need those customers.”

As she spoke, three women in shorts or short skirts lounged on sofas at the entrance. A fourth woman emerging from the back wore a T-shirt that said, “Love me, love me not.” The shop charges $30 for a half-hour massage, $45 for an hour. It also offers facials, skin peels and mud wraps. It advertises on Craigslist, highlighting “Absolutely Pretty Russian & Asian” and a “qualified massage therapist.”

Ms. Xu, who has been in the country 10 years and received a certificate at a beauty school, said she had trained many young women during those four years in various spa arts and some had gone on to open rival shops in the neighborhood. The competition, she said, has meant that “business is very slow.” She said she had heard about the complaints about paid sex and knew that “some people do this,” but she has cautioned her workers never to provide a sexual service even if men ask for it. She pointed out that all her rooms have windows that allow her to check on activities inside.

“I told the girls we’re 100 percent,” she said.

Tina Lee, a manager at King Spa, on Fifth Avenue, which opened two months ago, said they only offer “regular massage” and she displayed a menu of traditional Chinese medical techniques her shop offers, like foot massage, gua sha scraping of the back, hot stones and a brown mud application that she said was good for the heart.