Sacramento --

Gov. Jerry Brown's tax-raising ballot initiative has the support of a slight majority of registered voters, while a competing measure headed to the November ballot has little chance of passing, according to a Field Poll released Saturday. The poll found 52 percent of those surveyed said they would vote in favor of Brown's initiative, 35 percent were opposed and 13 percent were undecided. The measure would raise the income tax for seven years on individuals making $250,000 or more a year and the sales tax for four years.

The money would help fund education, along with a host of other state services. A public vote on tax increases has been the central focus for the governor since he took office last year. If it fails, Brown has proposed billions of dollars in spending cuts, mainly to education.

"He's got a lead. It's tenuous, but it's still a lead," said Mark DiCamillo, director of the Field Poll.

Complicating the governor's efforts, however, is a competing tax measure backed by wealthy civil rights attorney Molly Munger, who so far has put $8.3 million of her own money toward the effort. Brown has raised about $5.7 million from unions, corporations and Indian tribes, along with others.

Among those polled, 42 percent support the Munger initiative, 43 percent oppose it and 15 percent are undecided. Munger's initiative would raise income taxes for 12 years on a sliding scale for individuals making more than $7,316 annually, with the money dedicated almost entirely to public schools. Some of it would go toward paying off the state's debt. Historically, measures that are trailing this far before an election almost always fail, DiCamillo said.

"History would suggest its chances of passing are very, very slim," he said.

A spokesman for the governor's campaign responded to the results in a statement touting the margin between supporters and opponents.

"It's over 50 percent with a double-digit lead because it does what voters want - it puts California's finances back on a firm footing, ends cuts to education and protects public safety," said Dan Newman, the spokesman.

Brown's campaign team has raised concerns that Munger's effort will lead to the defeat of both measures. The poll also found that 4 percent of those surveyed support Munger's initiative but not that of the governor. It's a small number of people, but the final result of Brown's measure is expected to be decided by only a few percentage points.

The 4 percent "are voters Brown should have had and he's not getting. That is evidence that (Munger's initiative) is a little bit of a drag," DiCamillo said.

But Munger's campaign team is confident that their numbers will improve with aggressive campaigning for the measure.

"We can win, and we will win by running a solid field campaign, an aggressive TV campaign and a robust get-out-the-vote operation, and that's what we intend to do," said Nathan Ballard, spokesman for the effort. He said voters will have "a lot more information than is presented in a poll at this state" when they cast ballots in November.

While such a broad effort is expensive - likely in the tens of millions of dollars - Ballard said, "We're going to spend whatever it takes to communicate with voters on the airwaves about the benefits this measure will bring our schools."

Neither measure has been certified for the ballot, because county officials are still determining whether enough valid signatures were submitted for the efforts. Both are expected to qualify.

The poll was based on a telephone survey of 710 registered California voters. It was conducted from May 21 to 29 and has a margin of error of plus or minus 3.8 percentage points.