Spain's government-run Women's Institute has labelled a 2008 calendar for low-cost airline Ryanair featuring bikini-wearing air hostesses as sexist and said it would be sending letters of complaint to Irish and EU authorities.

The institute, which defends women's rights, said that while the fact that the proceeds from calendar sales would go to charity was positive, the photographs "represent the stewardesses as sexual objects" and "reinforce discriminatory stereotypes."

"It is significant that that only women are used, in a sector in which there is a considerable percentage of men," the institute, which is part of the Labor and Social Affairs Ministry, said in a statement.

The calendars show the hostesses - one for each month - posing in bikinis on or outside airplanes. They are sold on Ryanair flights and on the Internet with proceeds going to the Irish disabled children's charity Angels Quest.

"We're not talking about morals or nudity here, it's simply how women are portrayed," institute spokeswoman Maria Jesus Ortiz said. "If there had been men in the calendar, I'm sure there would have been no controversy."

The Spanish union of consumers FACUA raised the issue Tuesday.

Ortiz said the institute would send a letter of complaint to the Irish Embassy in Spain and to the European Union's gender equality group. Ortiz added that the institute was seeking legal advice on what further action it might be able to take.

Ryanair had defended the calendar, saying the hostesses had posed voluntarily and that it was for a good cause.