The Trust Act would bar police and sheriff's department officials from holding detainees for possible deportation unless the suspects were previously convicted of a serious or violent felony, the Los Angeles Times reported Friday.
The measure, which passed Thursday, is designed to blunt federal immigration enforcement, particularly the Secure Communities program, under which fingerprints are shared with immigration officials.
The legislation heads to the state Assembly, where opponents say they expect it to pass.
If signed into law, the measure would be another state legislative effort passed on behalf of California's estimated 2.55 million illegal immigrants, the Times said.
"Arizona and its governor may view all immigrants as criminals," Chris Newman, legal director for the National Day Laborer Organizing Network, told the Times, "but in California we have a different view."
Advocates said the measure would prevent illegal immigrants from being detained and possibly deported for relatively minor violations such as traffic infractions, misdemeanors and arrests that never led to a conviction. The California State Sheriffs' Association, which opposes the legislation, said the measure would put local law enforcement in the middle of state law and federal policy.
Since 2011, the Legislature approved financial aid for undocumented students and voted to reduce impoundment of vehicles driven by unlicensed drivers.