SACRAMENTO -- Early contributions to Gov. Jerry Brown's tax-hike initiative show a wide span of interests are beginning to line up behind it.

In the past two weeks, two business groups -- the Occidental Petroleum Corporation and the American Beverage Association -- pitched in $250,000 apiece to his ballot committee, Californians to Protect Schools, Universities and Public Safety.

The governor has raised $1.7 million as his campaign begins to collect signatures to place the initiative on the November ballot, according to campaign finance reports released Tuesday. No committee has yet been formed to oppose the tax measure.

Gaining the support of business alongside Democrats' traditional labor allies appears to be a key to the governor's strategy, analysts say. The measure would raise about $7 billion by increasing the sales tax by a half-cent and income tax on individuals who make $250,000 or more a year.

"The governor's hoping people will not see this simply as a sop to public employee groups," said Jack Pitney, a government and political science professor at Claremont McKenna College. "The danger is that opponents can portray this as the establishment versus the people, insiders versus outsiders. While support of big business may bring it a lot of money, it may also raise the suspicion level of many voters."

Previously, the California Association of Hospitals and Health Systems gave $500,000, the state building trades $250,000,

Two heavy hitters, the California Teachers Association and the California Medical Association, weighed in with endorsements in the past several days, and more big donations are in the offing as Brown seeks to raise about $4 million for signature gathering, said Steve Glazer, Brown's top political adviser.

"I'd describe our fundraising as robust," said Glazer, who ran Brown's 2010 campaign. "We're very optimistic about raising a lot more. This is just the start of the great breadth of support this measure will have."

But even as Brown worries aloud that other tax measures being proposed for the ballot could confuse voters and cause them to turn against all of them, two of the competing measures poured in big bucks to show they're still pushing forward with their own plans.

Molly Munger, a wealthy civil-rights attorney, just deposited $300,000 more into her campaign -- Our Children, Our Future -- on top of the $500,000 she'd already contributed from her personal wealth.

And the California Federation of Teachers this week dumped $500,000 into Restore California's campaign for a tax on individuals who make more than $1 million a year. It was the only contribution the campaign had received as of Tuesday -- a far cry from what's needed to gather enough signatures.

In what may be an even more expensive campaign, both sides in the upcoming battle over a "paycheck protection" measure have begun to amass their own war chests.

Stop Special Interests Now, the group seeking to prohibit unions from automatically collecting members' dues for political purposes, reported raising $1.8 million through Dec. 31.

Tim Draper, a Menlo Park venture capitalist, and William Edwards, a Palo Alto investor, both donated $100,000. The top donors are Edward Bloomfield, the Manhattan Beach billionaire laundry magnate, who gave $300,000; Larry Smith, an Orange County Republican activist who gave $235,000; and Charles Munger, Molly's brother, who so far has given $119,469.

The opponents, the Alliance for a Better California, raised $837,000 through Dec. 31, but have more than doubled it in the month since with $987,000 in contributions -- $500,000 of which came from the American Federation of State, County and Municipal Employees. Most of the rest -- $450,000 -- came from the Peace Officers Research Association of California.

In a reprise of an initiative that voters rejected in 2010, George Joseph, the 90-year-old billionaire chairman of Mercury Insurance, has poured in $8.2 million of his own money for a ballot measure to allow drivers to switch insurers without penalty.

Opponents, who have yet to create a campaign committee and who defeated the 2010 measure despite being outspent 15-to-1, argue that the measure is intended to create penalties for drivers who don't carry insurance continuously.

In a remarkable showing of fundraising prowess, former Obama administration official Ro Khanna, 35, of Fremont, raised more money in the fourth quarter of 2011 -- $1.2 million -- for a run in the 15th Congressional District than incumbent Rep. Pete Stark and two other candidates combined.

Khanna, however, has said he won't run for the seat until 2014 unless the 80-year-old Stark decides not to run this time around.

Staff writer Josh Richman contributed to this report.