SAN FRANCISCO -

Five California mayors have submitted a proposed ballot initiative that they say could fix the skyrocketing cost of public employees' retirement plans.

The measure, called the Pension Reform Act of 2014, would amend the state constitution to give government agencies authority to negotiate changes to benefits.

The mayors say it would protect retirement benefits that government employees have already earned but allow them to be modified for future years of service.

The mayors behind the proposal are Bill Kampe of Pacific Grove; Pat Morris of San Bernardino; Miguel Pulido of Santa Ana; Chuck Reed of San Jose; and Tom Tait of Anaheim.

They're hoping it will qualify for the November 2014 ballot.

Union leaders called the proposal extreme by letting public employers cut the retirement benefits promised to workers.