A large group of truck drivers joined a strike Wednesday at the nation’s largest port complex, alleging that they have been misclassified as independent contractors and denied benefits owed to employees.

At the Los Angeles and Long Beach ports, drivers from XPO Cartage, XPO Port Services and K&R Transportation walked off the job. Drivers from Intermodal Bridge Transport and warehouse laborers from California Cartage — K&R’s parent company — launched the strike on Tuesday afternoon.

The companies said the action is not representative of most truckers and accused labor organizers of disrupting the logistics industry for selfish gain. The workers said they would picket at marine terminals and the firms’ yards, warehouses and distribution centers to protest the alleged unfair labor practices.

Sergio Gonzalez, 47, said he has been driving for K&R for more than six years, hauling shoes, motorcycles and other items. The Huntington Park, Calif., resident said that K&R gave him his truck but requires him to make payments on it while also paying fees to cover his fuel, insurance and taxes.

“We have to pay for everything and the company takes most of the money,” Gonzalez said. “It’s so unfair.”

The ports have become a battleground between logistics companies and labor organizers attempting to unionize workers.

Strikers accuse the companies of improperly categorizing them as independent contractors or self-employed workers and then deducting operations and maintenance costs from their paychecks.

The classification prevents the drivers from claiming standard workplace protections, such as overtime pay, minimum wage, unemployment benefits and workers compensation, according to strikers.

When workers complained about the practice or attempted to unionize, some were fired or threatened, protesters said.

Long Beach-based California Cartage uses as many as 550 workers in its Wilmington warehouse, according to strikers. Of those, some 80 percent are employed through Core Employee Management, a subcontractor temp agency.

K&R, which declined to comment, also uses about 150 drivers at the ports.

XPO Cartage and XPO Port Services are part of XPO Logistics, which strikers said employs 200 drivers in the Los Angeles and Long Beach ports.

“The vast majority of the independent owner-operators we deal with take pride in their professionalism and don’t support actions aimed at interrupting the delivery of cargo,” XPO said in a statement.

Gary Schubert, president of Intermodal Bridge Transport, called the strike an “attack on the drayage industry” by the Teamsters labor union.

The effort to classify independent contractors as employees has “failed to gain any meaningful support” while contributing to “devastating results” on the industry, including multiple bankruptcy filings by logistics companies, departures by some businesses from the area and unionized drivers earning lower wages, Schubert said.

“IBT will meet the Teamsters’ challenge in any court of law and will not stand idly by while fundamental rights are being trampled,” he said. IBT is a national trucking firm owned by China-based COSCO Logistics.

Truckers have filed roughly 800 wage claims since 2011 due to employee misclassification, with more than $35 million awarded to drivers in more than 300 cases, according to the California Labor Commissioner’s office.

The same office began offering an amnesty deal in early May to trucking companies operating in ports that allowed applicants to recognize and pay back wages to employees improperly classified as independent contractors. In exchange, the companies would be free from related fines and penalties.