California Proposition 30: Support Wanes For Jerry Brown's Tax Plan

* Proposition 30 still ahead, but loses majority support

* Propositions 38, 32 trail; unions urge "no" on 32

SAN FRANCISCO, Oct 25 (Reuters) - Support is dropping for two California tax ballot proposals and a measure that would stop automatic payroll deductions for political activities by unions, a statewide poll shows.

Propositions are an important way for making policy in California, and hundreds of millions of dollars are being poured into fights over 11 measures on the Nov. 6 ballot.

Proposition 30, which would raise the sales tax for four years and hike income taxes on the wealthy for seven years, lost the slim majority support it had last month, according to the survey by the nonpartisan Public Policy Institute of California, which was released late on Wednesday.

Now 48 percent of likely voters say they would support the measure backed by Governor Jerry Brown, 44 percent would vote no, and 8 percent are undecided.

A competing tax plan by education advocate Molly Munger, Proposition 38, is losing with 53 percent opposed, 39 percent in favor and 9 percent undecided, the group said.

Likely voters were evenly divided on the measure in September.

Proposition 32, which would stop automatic paycheck deductions for political activities, is losing with 53 percent opposed, 39 percent in favor and 7 percent undecided.

The measure has drawn a tremendous "No" campaign from labor unions.

Pollsters interviewed 2,006 Californians, including 401 interviewed on cell phones, between Oct. 14 and Oct. 21. That included 993 likely voters, with the margin of error for that group at plus or minus 4 percentage points. (Reporting By Peter Henderson; Editing by Xavier Briand)