LOS ANGELES >> Troubles on the West Coast waterfront are getting worse.

Amid an increasingly damaging labor dispute, 29 West Coast seaports which handle about $1 trillion of goods annually will be mostly closed four of the next five days.

The announcement came Wednesday from the maritime association representing companies that operate marine terminals where dockworkers move containers of goods on and off massive ocean-going vessels, eventually putting the containers onto trucks or trains for distribution nationwide.

Companies now say they won’t hire crews to load or unload ships Thursday, Saturday, Sunday or Monday — when they’d have to pay holiday or weekend wages. Instead, smaller crews will focus on clearing already-unloaded containers off dockside yards.

Cargo has been struggling to cross the docks amid historically bad levels of congestion. Employers blame crowded docks on longshoremen staging work slowdowns; dockworkers deny slowing down and say companies are exaggerating to cut their shifts.

Differences over what is causing the congestion reflect disputes at the bargaining table.

Negotiations between the maritime association and dockworkers’ union for a new contract were to resume Wednesday in San Francisco, but were canceled despite heavy — and increasing — pressure from elected officials and businesses to reach a deal. The two sides last met Friday and a spokesman for the Pacific Maritime Association said the parties would reconvene Thursday morning.

The International Longshore and Warehouse Union had no immediate comment on the announcement from employers.