Saudi conservatives dominate many aspects of society
Twenty Saudi youths have been given 30 lashes each following disturbances on the country's national day, local reports say.
The Saudi press reported that gangs of hooligans had smashed shops in the eastern city of Khobar.
Other reports say clashes broke out when religious conservatives tried to stop the celebrations which they regard as blasphemous.
The public punishment allegedly took place in Khobar and nearby Dammam.
The original incident took place on the country's national day on 23 September.
Saudi newspapers have accused the youths of going on the rampage, claiming that shops and restaurants were smashed and in some cases looted.
The BBC's Sebastian Usher says the media have voiced serious concern over what would be a rare incident of unrest on the streets of the tightly-controlled kingdom.
Some Saudi websites say religious conservatives, offended when the young Saudis took part in festivities, provoked a violent confrontation.
Wahhabism is the dominant form of Islam practiced in the kingdom and followers adhere to a strict code of conduct.
Conservatives are said to be unhappy that a university opened on the day by King Abdullah was co-educational.