The logo of pornographic film production company Vivid Entertainment Group is seen on the building of its headquarters in Los Angeles, California January 11, 2013. REUTERS/Mario Anzuoni

LOS ANGELES - A top adult film producer sued Los Angeles County on Friday over a voter-approved measure requiring porn actors to wear condoms, saying the law infringes on their First Amendment rights and was driving the industry out of southern California.

Vivid Entertainment, which was joined in the lawsuit by porn stars Kayden Kross and Logan Pierce, claims the mandate is both an unconstitutional prior restraint on freedom of expression and a financial burden that studios could not bear.

“You don’t have to win an Oscar to be protected by the First Amendment,” the lead attorney for the plaintiffs, Paul Cambria, told Reuters after filing the lawsuit in U.S. District Court in Los Angeles.

The complaint also alleges that the ballot initiative known as Measure B, which was approved by 56 percent of county voters in November, treads into an area regulated by the state.

The plaintiffs are seeking an injunction that would block implementation of Measure B, which requires porn actors filming in Los Angeles County - the heart of the massive U.S. adult film industry - to wear condoms during sex scenes.

Representatives for Los Angeles County, its chief public health official Kenneth Fielding, and District Attorney Jackie Lacey, who were also named as defendants, declined to comment on the legal action on Friday afternoon.

But an attorney for AIDS Healthcare Foundation, which sponsored the measure, predicted that the lawsuit would fail.

“Despite what the adult industry’s lawyers are claiming in this lawsuit, Measure B is not directed at speech and as such their First Amendment claims will likely ring hollow with the court,” the group’s general counsel, Tom Myers, said in a written statement.

The law also orders producers of adult films to pay a fee to the county’s Department of Public Health and obtain a permit that requires all principals and management-level employees to undergo blood-borne pathogen training.

“They’re telling the production house that in order to produce legally protected expression, you have to first get government approval and you have to agree to shoot it in particular way, namely with condoms,” Cambria said.

Cambria said the industry already had a system of testing for sexually transmitted diseases that worked well and that the new condom law was prompting adult film studios to leave southern California, heading overseas or to Mexico.

“I can tell you they are leaving L.A. County in droves,” he said. “It’s a multi-billion dollar industry that employs thousands of people, and ever since this all started they have been leaving and filming in places other than L.A. County.”

Cambria said that if studios leave Los Angeles County because of the law then adult film workers would have less protection, not more, because “what you’re doing is taking it to a place where there will be no rules.”

He said it was not economically feasible to digitally remove the condoms in post-production because the studios were competing with rivals elsewhere who had no such restrictions.