Prince Fahd bin Badr, governor of the northern al-Jof region, ordered police to carry out the punishment after seeing a group of men with long hair pestering female students as they left school in the northern al-Qurayat province, Al-Hayat newspaper said.
It said the prince told a gathering at his palace in the northern town of Skaka on Sunday he has instructed police to apply the punishment to all youths guilty of flirting, including "the sons of senior military and civil officials."
"The decision doesn't include men who spend their free time in public places without hurting anyone," the paper quoted the prince as saying.
Saudi Arabia has long imposed a strict Islamic lifestyle in which men and women are segregated in public. That lifestyle is enforced by the Commission for the Promotion of Virtue and the Prevention of Vice, a government body that runs the country's powerful religious police.
Its members patrol public places to make sure women are covered and not wearing make up, the sexes don't mingle, shops close five times a day for Muslim prayers and men go to the mosque and worship.
Many clergymen in this conservative Gulf country say men should not have long hair because Islam prohibits the sexes from emulating each other.
Sheik Mubarak al-Rushoud, head of the commission in al-Jof, told Al-Hayat the new punishment resulted from "the repeated pestering of women in souks and outside girls' schools."
He said Fahd has ordered that the punishment against the men "who emulate women" should be carried out at the scene of the infraction, according to the paper.
"The decision, however, doesn't include all men with long hair," al-Rushoud was quoted by Al-Hayat as saying.