"Access to social media allows inmates to circumvent our monitoring process and continue to engage in criminal activity," California Department of Corrections and Rehabilitation Secretary Matthew Cate said in a statement posted on the prison system's Web site.
The department is reporting inmate pages to Facebook, which says it will remove pages found to have been updated since the page owners went to prison, the Los Angeles Times reported Tuesday.
Contraband cellphones that inmates use to surf the Web and update social media pages are a growing problem, authorities say.
Prison employees, who do not have to submit to searches when entering prisons, are suspected as the primary source of contraband phones that can bring as much as $1,000 each.
A pending bill in the state Senate would make smuggling a phone to an inmate a crime punishable by a $5,000 fine and up to six months in jail, the Times reported.