She had triggered a huge backlash on the social media after posing for a picture without hijab in a main Riyadh street last month.
The Post reported that police have not revealed her name and that many websites have identified her as Malak al-Shehri.
He spokesperson also said that in addition to violating the dress code Malak is also facing charges for indulging in relationships outside her family with non-related men.
"Riyadh police stress that the action of this woman violates the laws applied in this country", Maiman said.
All women in Saudi, even those who immigrate from other countries, are mandatorily asked to cover from head to toe when going out in public.
Due to the vehement criticism generated by her post, Malak made a decision to delete it and she also deleted her Twitter page.
Another said: "We want blood".
All women in Saudi Arabia - local and foreign - are legally required to wear an abaya - which is a traditional full-body covering.
Once the news of her arrest was released, some tweeted in approval of the authorities' actions. Others, though, responded with messages of support.
Saudi Arabia is one of the very few countries that has imposed medieval-like restrictions on women and is also the only country in the world to prevent women from getting a driving license. While women were granted the right to vote in last year's municipal elections, laws still bar them from driving and require that they obtain permission from either their husbands or male relatives in order to obtain a passport, travel, or marry.
"It's time for women to drive", reports The Guardian.