TEHRAN (Reuters) - Iran's prosecutor called on Sunday for tighter checks on women who fail to observe Islamic dress code in public, the semi-official Mehr news agency reported.Under Iran's Sharia law, imposed after the 1979 Islamic revolution, women are obliged to cover their hair and wear long, loose-fitting clothes. Violators can receive lashes, fines or imprisonment. "Unfortunately the law ... which considers violation of the Islamic dress code as a punishable crime, has not been implemented in the country in the past 15 years," said general prosecutor Gholamhossein Mohseni-Ejei.

"Under the law, violators of public chastity should be

 punished by being sentenced to up to two months in jail or 74 lashes."

Strict dress codes were enforced in the years after the revolution but in recent years clamp downs have tended to last just weeks or months in summer, when women wear lighter clothing such as calf-length trousers and colored scarves.

Young women in urban areas often defy the limitations by wearing tight clothing and colorful headscarves that barely cover their hair. The codes are less commonly flouted in rural regions.

Enforcement of codes governing women's dress have become stricter since President Mahmoud Ahmadinejad took office in 2005, promising a return to the values of the revolution.

The president's hardline supporters, who say Islamic attire helps protect women against the sex symbol status they have in the West, have pressed for tighter controls on "immoral behavior."

"It is up to the judge to decide whether to punish violators by only fining them," said Mohseni-Ejei.

(Writing by Ramin Mostafavi; Editing by Janet Lawrence)