A union representing 22,000 dockworkers at 29 US West Coast ports and a body that represents employers have reached a tentative agreement after more than a year of negotiations, possibly ending months of labour disputes that could impact the nation’s economy.

The International Longshore and Warehouse Union (ILWU) and the Pacific Maritime Association (PMA), which represents terminal employers and ocean carriers, have announced a tentative deal on a six-year contract that acting US labour secretary Julie Su helped put in place.