MEXICO CITY — A campaign aimed at halting the illegal consumption of endangered sea turtles' eggs has run into trouble before it starts, with a women's group asking officials to block public-service announcements featuring a scantily clad model.

"My man does not need turtle eggs. Because he knows they don't make him more potent," Argentine model Dorismar purrs from posters in which she poses alternately in sexy bathing suits, skimpy shorts and an unbuttoned shirt and cowboy hat.

The message, designed by the nonprofit, California conservation group Wildcoast, is aimed at Mexican men who for years have eaten the eggs, believing they are aphrodisiacs.

The National Women's Institute considers the campaign offensive and a step back in the country's bid to overcome its culturally ingrained machismo.

"The institute is against this campaign because it promotes women as sexual objects. We are not against the campaigns that protect turtles and their eggs, just the way in which they use the woman, as a stereotype or sexual object," the group said in a statement.

It added that the ads represent "a setback in the fight for women's rights and the public policies the government is promoting in terms of gender issues."

Government officials distanced themselves from the ads and issued public statements stressing that they are not the ones sponsoring them.

Wildcoast has no plans to back down, although it decided to remove any reference to government agencies on the posters, which are scheduled to be put up in several Mexican states in September, said Aida Navarro, Wildcoast's wildlife-conservation-program manager.

"We are not trying to offend anybody," Navarro said in a telephone interview. "This is about saving the turtles, and we do believe that this message definitely helps to reach the audience we are trying to reach."

The group launched its campaign in April, when it began distributing informational materials that included postcards with Dorismar's image, Navarro said.

Although consuming the eggs is illegal, they can be found in black markets everywhere from the Pacific beaches, where most sea turtles nest, to Mexico City.

Poachers use the turtles' shells for combs, their flippers for handbags, their meat for soup and their eggs as an aphrodisiac.

According to the most recent Mexican government statistics available, the number of turtle eggs stolen rose from 140,000 in 2001 to 231,000 in 2003, while more than 230 people were arrested during those years for trafficking turtle products.