SACRAMENTO — Proponents of an auto insurance discount initiative — backed financially by the chairman of Mercury General Corp. — are accusing the state attorney general and their opponents of submitting incorrect statements for the official ballot pamphlet.

The campaign to pass Proposition 33 in November filed a lawsuit on Friday contending that the legal "title and summary" that is to be put before voters contains "inaccurate language that is highly likely to prejudice voters against the measure."

The suit quibbles with the attorney general's statement that Proposition 33 would change "current law to allow insurance companies to 'set prices.'" The term, the suit argued, has negative connotations linked to illegal price fixing.

The attorney general's office disputed the allegation. Spokeswoman Lynda Gledhill called the title and summary "both fair and accurate."

The proposition, which has been backed by a $8.3-million contribution from Mercury Chairman George Joseph, would allow insured motorists to change insurance companies and continue to receive the so-called loyalty discount they previously got from their former insurance company. A similar measure failed to win voter approval in 2010.

Opponents of the initiative counter that passage of Proposition 33 would hurt low income and new drivers by making it more expensive for them to buy insurance for the first time. Proposition 103, an auto insurance reform initiative approved by voters in 1988, mandates that rates be calculated mainly by using three factors: a driver's record, number of years a driver has had behind the wheel, and miles driven per year.

"[Proposition 33] allows insurance companies to do something they've not been able to do," said Harvey Rosenfield, the author of Proposition 103. "They will be allowed to surcharge people who didn't buy insurance in the past just because they did not buy insurance."

Lawsuits seeking changes in initiative titles and summaries, as well as in arguments for or against the proposals, aren't uncommon, said Evan Goldberg, chief deputy to California Secretary of State Debra Bowen.

The secretary of state, though named as a party in the lawsuit, takes no position on the content of either the title and summary or the two sides' arguments, Goldberg said.

However, Goldberg urged a Sacramento Superior Court judge to make a speedy ruling because deadline for printing voter guides is Aug. 13.