(CNN) -- Half of all Californians support Arizona's controversial new immigration law, but the measure, which is a hot topic in next week's primaries, is dividing Golden State voters by age, ethnicity, and gender, according to a new poll.

A USC/Los Angeles Times survey released Monday indicates that 50 percent of California voters favor the Arizona measure, with 43 percent opposed and five percent unsure. Support for the law is higher in most national polls conducted over the past two months.

"California voters support the Arizona law, but not nearly by the margins we've seen in other parts of the country, " says Dan Schnur, director of the Jesse M. Unruh Institute of Politics at USC.

The recently enacted Arizona law initially allowed police to ask anyone for proof of legal U.S. residency, based solely on a police officer's suspicion that the person might be in the country illegally. Arizona lawmakers soon amended the law so that officers could check a person's status only if the person had been stopped or arrested for another reason.

Critics insist the law will lead to racial profiling; supporters deny the charge and insist the measure is needed to crack down on increasing crime involving illegal immigrants.

According to the poll, 58 percent of Californians age 18 to 29 oppose the Arizona law, with people age 30-44 split. Fifty-three percent of people age 45-64 back the measure, and 57 percent of people 65 and older support the law.

Fifty-three percent of men questioned in the survey favor the law. That number drops to 47 percent for women questioned in the poll.

The survey also indicates a ethnic divide, with more then seven in 10 Hispanics opposed to the law and nearly six in 10 white voters supporting the measure. Fifty-seven percent of Asian voters oppose the law, with African Americans evenly divided.

Sixty-two percent of Democrats oppose the law, while 48 percent of Republicans support the measure.

The poll suggests the law could have an impact on how Californians vote: One-third of those who oppose the law and one-fifth of those who back the measure say there's "no chance" they would vote for a candidate who disagrees with their stance on the issue.

"Opponents of the law seem much more emotionally engaged than supporters: our poll shows that a candidate's position on this issue is more likely to motivate an opponent of the new law to change their vote than a supporter," says Schnur.

According to the poll, 48 percent of California voters oppose new offshore drilling for oil in their state, a 10 point turnaround from last year. The survey indicates a partisan divide, with nearly two-thirds of Democrats opposed and just over two-thirds of Republicans supportive of new offshore drilling off the California coast.

"When Californians were paying four dollars a gallon for gasoline a few years back, support for offshore drilling grew very rapidly," adds Schnur. "When those same voters look at pictures of the Gulf spill, they're not nearly as excited about the idea."

The poll also indicates than 52 percent likely California voters back a ballot measure that aims to dramatically alter the state's primary process. Less than three in ten say they would vote against the measure and one in five is undecided. The proposal would allow all voters to cast ballots for any candidate in a primary, regardless of party affiliation. The proposed measure calls for the top two vote-getters to advance to the general election.

The USC/Los Angeles Times poll was conducted May 19-26, with 1,506 California registered voters questioned by telephone. The survey's overall sampling error is plus or minus 2.6 percentage points.