An initiative that would bring health insurance rate regulation to California has qualified for the November 2014 ballot, setting the stage for a vigorous and costly battle between insurers and consumer groups.

The measure, sponsored by Consumer Watchdog, would give the state insurance commissioner the power to deny certain premium increases if they are deemed excessive.

The insurance commissioner has little control over such rate hikes now.

The initiative would apply to the individual and small group health insurance markets, but large employer group plans would be exempt.

"We're thrilled that voters will get the chance to decide whether or not it's time to rein in outrageous rate hikes," said Carmen Balber, a spokeswoman for the Consumer Watchdog campaign.

"We expect a battle royale," she added. "We have no doubt that the health insurance industry will throw down tens of millions of dollars to oppose this."

Opponents have already begun to organize their campaign.

"This flawed, costly measure is not real health reform," said Patrick Johnston, president and CEO of the California Association of Health Plans, in a statement. "This measure would give one politician too much power over health coverage, do nothing to address the underlying costs driving health care premiums and create an expensive and duplicative state bureaucracy that will be paid for with higher health insurance premiums."

Consumer Watchdog had hoped to qualify the initiative for this year's ballot. But after a random sample of petitions failed to produce enough valid signatures, counties did a full signature check, pushing the count past the deadline for this November's election.

On Thursday, the Secretary of State's office announced that Consumer Watchdog had gathered the required 504,760 signatures.

Balber said having the election in 2014 may be good timing because it will occur as the national health reform law takes full effect, including a mandate that most Americans have coverage.

"The price and affordability of health insurance will be at the top of Californians' minds," she said.

Sandy Kleffman covers health. Contact her at 510-293-2478. Follow her at Twitter.com/skleffman.