The protesters, including psychologists and psychiatric professionals, put up barricades outside the downtown facility, demanding better salaries and employee benefits, as well as shorter waiting times for patients.

Organizers said the strike came after more than a year of negotiations between Kaiser employees and management over patient care and employee workload.

The demonstrators are members of the National Union of Healthcare Workers (NUHW), which represents 15,000 Kaiser employees.

A protester, who requested to remain anonymous, said Kaiser had promised to hire more people to relieve the burden on employees but failed to take action.

The Kaiser workers who took to the streets on Monday were supported by California Senator Scott Weiner, who joined the protesters on the day.

"Today I stand with Kaiser mental health professionals, as they fight for better patient access to mental health services. We have a huge problem with the lack of access to mental health services. We must expand access, and Kaiser needs to be part of the solution," he said.

According to protest organizer the NUHW, Kaiser mental healthcare patients "get shunted to phone calls before they can ever see a clinician. It takes weeks and weeks to see a caregiver face to face," it tweeted.

Monday's demonstration kicked off a five-day strike by Kaiser psychologists, therapists, psychiatric nurses and other healthcare professionals across California, which will involve more than 100 Kaiser clinics and medical facilities across the state, NUHW officials said.