A former unpaid intern for the fashion magazine Harper’s Bazaar filed a lawsuit on Wednesday, accusing its parent company, the Hearst Corporation, of violating federal and state wage and hour laws by not paying her even though she often worked there full time.

In her lawsuit, filed in Federal District Court in Manhattan, the intern, Xuedan Wang, and her law firm are asking to make the case a class action on behalf of what they say are hundreds of unpaid interns at Heart Magazines, which also publishes Cosmopolitan, Seventeen and Good Housekeeping.

Employment experts say a growing number of young people, hundreds of thousands of them, do unpaid internships each year as they seek to get a foot in the door and gain work experience. But some interns and labor advocates assert that many employers are taking advantage of these interns — and violating Labor Department rules in the process — by using the interns essentially to do the jobs of other workers and not providing a bona fide educational experience.

The lawsuit against Hearst states, “Employers’ failure to compensate interns for their work, and the prevalence of the practice nationwide, curtails opportunities for employment, fosters class divisions between those who can afford to work for no wage and those who cannot, and indirectly contributes to rising unemployment.”

According to the lawsuit, Ms. Wang, who graduated from Ohio State University in 2010, was an intern at Harper’s Bazaar from August 2011 to December 2011 and said she generally worked 40 hours a week but sometimes as many as 55 hours. Her lawyers said that Ms. Wang, with a degree in strategic communications, coordinated pickups and deliveries of fashion samples between Harper’s Bazaar and fashion vendors and showrooms and assigned other unpaid interns to help carry out the pickups and deliveries.

She also helped maintain records on the fashion samples and process reimbursement requests for corporate expense reports.

“Unpaid interns are becoming the modern-day equivalent of entry-level employees, except that employers are not paying them for the many hours they work,” said Adam Klein, one of the lawyers for Ms. Wang. “The practice of classifying employees as ‘interns’ to avoid paying wages runs afoul of federal and state wage and hour laws.”

Hearst, like many other media companies, does not pay its interns, but officials say it arranges for them to receive academic credit through their college or university. Hearst officials said that this arrangement is made clear to prospective interns in advance.

A spokesman, Paul Luthringer, said: “We have not been served with any such lawsuit and thus cannot comment at this time.”

The lawsuit pointed to guidelines from the United States Labor Department, which state that unpaid internships are only lawful in the context of an educational training program, when the interns do not displace regular employees and the employer derives no immediate advantage from the intern’s work. The guidelines also state another criterion for internships to be unpaid: “the internship experience is for the benefit of the intern.”

Ms. Wang’s lawyers said that by treating her and others as interns rather than regular employees, they were denied not only wages, but also Social Security contributions and the right to receive unemployment insurance and workers’ compensation.

Last September, Mr. Klein’s Manhattan-based law firm, Outten & Golden, filed a lawsuit against Fox Searchlight Pictures, accusing it of violating wage laws by using unpaid interns to work on “Black Swan” and other films. Fox Searchlight has denied any wrongdoing.