"We're withholding services until further notice," said viola player David Gaudry, who joined dozens of other musicians outside Davies Symphony Hall Wednesday morning to announce the work stoppage.
A concert by the symphony scheduled for Thursday afternoon has been canceled, and other concerts at the symphony hall this weekend and an upcoming East Coast tour are also in doubt because of the labor dispute.
"We do not wish to go on tour without a contract," said Gaudry, who chairs the musicians' negotiating committee.
The musicians' most recent contract expired on Feb. 15, and they are unhappy with the latest three-year proposal by management, which included a pay freeze in the first year and 1 percent increases in the following two years.
On average, San Francisco Symphony musicians make more than $165,000 a year, making them the third highest-paid symphony the country, behind only Chicago and Los Angeles.
However, Gaudry said, they have to pay for their own instruments, which can cost hundreds of thousands of dollars, and live in the costly Bay Area.
"We will not be able to hold onto our most talented players," he said, noting that one of their top timpanists recently took a job with the symphony in Chicago.
Gaudry said the musicians are asking for a 5 percent pay increase -- about $7,500 per year -- in order to be on par with the other two top symphonies.
Brent Assink, executive director of the San Francisco Symphony, said he is "deeply disappointed" by the musicians' decision to strike and said he regrets any inconvenience caused to customers.
Assink said management would "continue to work hard to come up with a fair agreement that gives our talented musicians a contract that reflects our stature as one of the top orchestras in the country, but also sets a prudent financial course for the future."
He said the organization is seeking to balance its budget, having operated on a deficit for the past four years.
The symphony's next proposal to the musicians will come on Thursday when the two sides plan to meet, he said.
People with tickets to Thursday's concert can contact the symphony's box office at (415) 864-6000 to receive a refund or exchange the tickets for an upcoming concert.
The latest information on future concerts and the status of the labor dispute can be found online at www.sfsymphony.org.
The symphony's musicians have held previous strikes in the past, including a nine-week stoppage in 1996 and 1997.