By David Shepardson

WASHINGTON (Reuters) -Acting U.S. Labor Secretary Julie Su is in California to meet with West Coast ports unions and the employers' Pacific Maritime Association to encourage them to stay at the bargaining table and reach an agreement, the department said Tuesday.

Last week, the U.S. Chamber of Commerce urged President Joe Biden to intervene immediately and appoint an independent mediator to address a West Coast ports labor dispute. More than 22,000 dockworkers at ports from California to Washington state have been working without a contract since July 2022.

On Monday, West Coast seaport employers criticized worker absences, which they said were slowing work at some of the nation's busiest ports, as unions press for a bigger share of record profits reaped when cargo shipments surged during the pandemic.

West Coast ports stretching from California to Washington state are critical to U.S. supply chains and the nation's economy. Contract talks have entered their 13th month.

The Pacific Maritime Association (PMA), representing terminal operators with ties to the shipping companies that enjoyed a hefty financial windfall from COVID-19, said port operations in Los Angeles, Long Beach and Seattle on Sunday suffered disruptions due to labor shortages.

Weekend operations at many U.S. seaports are limited, seaport operators said. Still, several have confirmed that worker absences have slowed or stopped work during the talks. For example, ships have been delayed at berth at the No. 1 U.S. container gateway at Los Angeles/Long Beach, due to a lack of "lashers" who secure and unlock containers onboard vessels.

On Saturday, International Longshore and Warehouse Union (ILWU) President Willie Adams said "West Coast ports are open as we continue to work under our expired collective bargaining agreement." He reiterated the union's intention of reaching an agreement. Su is meeting with both ILU and PMA, the department said.

If talks fall apart, mediation fails and port operations cease, Biden can invoke federal labor law to force resumption of normal port operations. The last president to do that was George W. Bush, who invoked that federal law in 2002 after port employers locked out union longshore workers.

(Reporting by David Shepardson; Editing by Chizu Nomiyama)