Thousands of clerical workers and administrative support staff waged a strike Tuesday across University of California campuses, including in Los Angeles, Riverside and Irvine, as part of a one-day walkout calling for higher wages and better benefits.

At UCR, about 40 protesters picketed two sites on campus during the action by employees represented by the Teamsters.

The employees were mostly clerical workers, although child care workers are also represented by the union. UCR’s day care center was closed for the day as a result.

UC officials and the Teamsters have been in negotiations since last April. Union representatives have said the UC is not negotiating in good faith. A statement from UC President Janet Napolitano said workers are being offered an average 18 percent pay increase over six years.

John Valdez, 46, has worked in budget and payroll offices at UCR for nine years. He is the union’s on-campus coordinator. He said he would like to see a 4 percent per year increase in pay. The strike, he said is meant to get the attention of UC officials and the public.

“I’m hoping it will show them we are concerned,” Valdez said, as a passing truck with the UCR emblem on its door, honked in apparent support of the strikers. “I think statewide we’ll have a good impact.”

Valdez said the UC “typically pays lower wages,” and cited a study by Occidental College released in October, which reported that 70 percent of workers in clerical or administrative support positions struggle to feed themselves and their families.

The report found the workers made an average of $22 per hour and most have college degrees.

Striker Leslie Settle, 33, works in the UCR library. An alumni of the campus, she has a master’s degree in public administration. She said the $2,200 she takes home every month leaves her living paycheck to paycheck. With a home in Moreno Valley and two children in private school, she said she still contributes regularly to the university’s guardian scholarship program.

A pay increase, she said, would mean “I would have more of a sustainable living. I could save some money.”

At UCLA, where union organizers said hundreds walked off the job, research analyst Timothy Mathews of Teamsters Local 2010 said members of the clerical unit were largely protesting wages that “haven’t kept up with (the) cost of living.”

Union leaders have been negotiating with UC administrators for a new contract for these employees, which include administrative assistants, public safety dispatchers, library assistants and child care teachers, since April after contract negotiations faltered last year, largely over salary increases.

The UCLA campus and its medical facilities remained open and operational throughout the strike on Tuesday, said Rebecca Kendall, a senior media relations officer in an email.

In a statement, UC said it’s offering clerical employees at each of its campuses “guaranteed, market-competitive wage increases,” including an average pay raise of 18 percent over the next six years as well as “excellent health care benefits and retirement options.”

“UC clerical employees earn an annual average salary of $47,300 — more than the state average of roughly $39,200 for clerical workers,” the statement said. “These UC employees typically pay just $384 a year for health insurance for themselves and their children. By comparison, the average American worker typically pays over $5,200 for less generous health coverage — and that’s just for themselves.”