The International Longshore & Warehouse (ILWU) and the Pacific Maritime Association (PMA) have reached a tentative agreement on a new collective bargaining agreement for US West Coast dockworkers, ending a gridlock followed by several strike actions that pose to disrupt operations at some of North America's busiest cargo ports.

The agreement announced Wednesday covers dockworkers at all 29 ports from California to Washington and needs to be ratified by both parties.

"This afternoon, the leaders of the International Longshore and Warehouse Union and the Pacific Maritime Association reached a tentative agreement covering 22,000 workers and 29 West Coast ports, demonstrating once again that collective bargaining — though sometimes difficult — works," said Julie Su, acting US labour secretary, who travelled to San Francisco this week to get stalled negotiations, which has been stalled since June, back on track.

"Thanks to the hard work and perseverance of the leadership of the ILWU and the PMA, the tentative agreement delivers important stability for workers, for employers and for our country's supply chain," she added. "This important milestone is welcome news to all, and on behalf of President Biden, we are pleased to congratulate both parties on what they have achieved."

The new tentative agreement is for a new six-year contract, although both PMA and ILWU said they would not be releasing details of the agreement at this time.

James McKenna, president of PMA, and Willie Adams, president of ILWU, also welcomed the tentative agreement noting that stakeholders could now channel their full efforts to port operations.

"We are pleased to have reached an agreement that recognizes the heroic efforts and personal sacrifices of the ILWU workforce in keeping our ports operating," McKenna and Adams said in a joint statement.

"We are also pleased to turn our full attention back to the operation of the West Coast Ports," the PMA and ILWU chiefs added.

Growing concerns have emerged about the potential for a repeat of the 2002 situation, where a lockout by the PMA in response to ILWU worker slowdowns resulted in an 11-day closure of US West Coast ports.

In recent weeks, worker slowdowns have been observed at ports throughout the US West Coast, with container terminals at the Port of Seattle experiencing closure last weekend.

Gene Seroka, executive director at Port of Los Angeles, said the tentative agreement between the ILWU and PMA brings the "stability and confidence that customers have been seeking" at West Coast ports.

"We're grateful to Acting Secretary of Labor Julie Su, ILWU International President Willie Adams and PMA President James McKenna for their leadership and resolve. We look forward to collaborating with our partners in a renewed effort to bring back cargo and demonstrate why Los Angeles is the first choice for Trans-Pacific trade," Seroka said.

Port of Long Beach called the tentative agreement a "momentous achievement."

"This is great news for the West Coast ports and the supply chain all across America. The contract agreement will have a hugely beneficial impact on the U.S. economy, which depends on our ports and the trade they facilitate. The goods movement workforce and industries provide a crucial and often unheralded service to society by keeping cargo flowing and shelves stocked," the port said in a statement.

"The importance of this work cannot be overestimated, and we are fortunate to have so many dedicated individuals devoting their careers to it — people near and far," Port of Long Beach added, as it expressed "most sincere thanks" to the negotiators from both sides who worked so hard and diligently to reach this landmark agreement.

The announcement of a tentative agreement between the PMA and ILWU was also lauded by shippers.

"On behalf of the retail industry, we are relieved to see the parties have come to a tentative mutual agreement on a long-term contract … ending over a year of negotiations and uncertainty," The National Retail Federation (NRF) said.

"The West Coast ports are a critical artery for retailers and other businesses into the US market. We urge the parties to quickly ratify the tentative agreement to bring certainty back to the West Coast ports," it added, noting that it is essential to begin the negotiation process early for the next labour contract and avoid a future lapse in continuity.