The groundswell of populist anger against banks and politicians picked up momentum in Southern California as powerful labor union support helped galvanize protests nationwide.

Rallies extended to the 18th day in New York, where Occupy Wall Street planned a massive solidarity march with unions Wednesday. Protesters spent their fourth night camping outside Los Angeles City Hall, disrupted a bankers conference at a Newport Beach yacht club and demonstrated outside a financial executive's Bel Air home.

The movement has spread nationwide, from Boston to Kona, Hawaii, taking inspiration from the social-media-driven Arab Spring revolts in the Middle East. The anti-corporate push even got a nod from Federal Reserve Chairman Ben S. Bernanke, who said of protesters: "On some level, I can't blame them."

Photos: 'Occupy LA' protest

Protests on the West Coast have drawn an assortment of activists, from college students to anarchists to ordinary Americans worried about the economy. They have no single organizer, and instead are made up of individual groups focused on what they see as the banking industry's role in the growing divide between America's rich and poor.

"The banks engineered the country's financial collapse and then profited from it," said Joe Briones, 29, a film major at L.A. City College who is helping to run the Occupy LA social media feed from the City Hall protests. "They did the same thing in the Depression."

With this same attitude, protesters disrupted a meeting of the California Bankers Assn. at the Balboa Bay Club in Newport Beach. About 40 members of ReFund California, a coalition of advocacy groups and union members, burst into the club's ballroom, chanting, "Make banks pay!"

The bankers association president, Rodney K. Brown, said protesters "muscled their way" past hotel security and wanted only to "chant and rant" instead of engage in a constructive dialogue. The bankers listened as protesters accused them of causing the economic meltdown by peddling bad loans, accepting government bailouts and then doing little to compensate for the damage inflicted.

Police stood by as protesters were ushered back to West Coast Highway, where members of the Service Employees International Union and the liberal group MoveOn.org chanted, "Shame, shame, shame!"

"You've made your point. Now get out," Balboa Bay Club security chief Drew Witthuhn said as the group shuffled out into the rain.

ReFund California also protested at the Bel Air home of Steven T. Mnuchin, chairman of OneWest Bank of Pasadena. The group demanded help for borrower Rose Gudiel of La Puente, saying OneWest callously foreclosed on her family home after her brother's death caused delinquencies on her home loan.

A Mnuchin spokesman said OneWest was only doing what Fannie Mae, the owner of the loan, required.

The group said it planned a similar confrontation outside the home of another bank executive Wednesday. Activists are expecting big turnouts for marches held on both coasts Wednesday.

In New York, several unions and advocacy groups plan to march from City Hall to Zuccotti Park, just days after a more impromptu march led to the arrest of 700 protesters. The 700,000-member Communications Workers of America said it supports "nonviolent efforts to seek a more equitable and democratic society based on citizenship, not corporate greed."

Occupy LA was expecting a big turnout for its own march, though its numbers in about a dozen tents had fallen in recent days. The plan was to take trash collected in a South Los Angeles neighborhood blighted by foreclosures and dump it at a bank that protesters blame for causing the urban decay.

Participants, acknowledging they were promoting widely varied causes, also discussed the need to agree on a clear, focused message.

"People are going to say stupid things," said Vincent Vibbert, a shaved-headed, work-booted organizer who offered advice from time he had spent at the Wall Street camp-in. "You've got to make sure that people who are well-spoken jump in front of the TV cameras."

In an only-in-L.A. twist, the protesters have been walking a block to the county criminal courts building to attract attention from news media covering the trial of the doctor who was attending to pop star Michael Jackson when he died.

Photos: 'Occupy LA' protest

scott.reckard@latimes.com

Times staff writer Nathaniel Popper in New York contributed to this report.