San Francisco's 4-year-old, mandatory sick-leave law has gained wide acceptance among employees and their bosses, a new study by the Institute for Women's Policy Research says.

The voter-approved law, the only one of its kind in California, gives workers one hour of paid sick leave for every 30 hours on the job. Workers can accrue up to five days at any given time at companies with less than 10 employees and nine days at any given time at those with more than 10.

Surveys of 700 employers and 1,200 employees by the Washington institute found that two-thirds of employers support the San Francisco law, and only 1 in 7 employers complained that it affected their profitability.

The typical worker covered by the law used only three days per year to stay home sick or to care for children or relatives, the study said. One quarter of employees queried took no time off for illness.

"San Francisco's policy helped parents, workers with chronic diseases, low-wage workers and others with minimal impact on employers," said report co-author Vicky Lovell. "The paid sick leave ordinance serves as a model for the rest of the country."

A bill to expand the San Francisco program statewide is expected to be introduced this year in the state Legislature by Assemblywoman Fiona Ma (D-San Francisco). Similar bills failed in previous years.

"Nobody wins when workers show up to work sick," Ma said. "The lack of paid sick days is a public health concern. It harms children and families and decreases productivity at work."

It's important for workers to be able to stay home when they are sick, said Daniel Conway, a spokesman for the California Restaurant Assn. But arranging for time off should be left to informal arrangements between restaurant owners and their employees, he said.

"We're looking to give employers and employees maximum flexibility. That's something unique to the restaurant industry," Conway said."Mandates by their very nature negate that flexibility."