Around 104 organisations - including those representing US apparel, retail and footwear firms - have joined forces to urge unions to conclude West Coast ports talks amid growing concerns over delayed shipments.

In a letter to the International Longshore and Warehouse Union (ILWU) and Pacific Maritime Association (PMA), the organisations which include the American Apparel and Footwear Association (AAFA), the National Retail Federation (NRF) and the National Cotton Council, said many stakeholders are already experiencing "severe negative effects".

They warned the situation will soon start to have a broader impact on the US and North American economies.

"We fully respect the collective bargaining process and understand the importance of the remaining issues for both management and labour. However, our members are concerned that there has been no visible progress in the negotiations since August, when the ILWU and PMA announced a "tentative deal" on health benefits," the signatories said.

"As we noted in our letters of May 9th and July 9th, the financial and economic situation for thousands of importers and exporters who rely on the West Coast ports, and their millions of employees and business partners, rest on the timely conclusion of a new port labour contract."

The organisations said they understood the need for a media blackout during negotiations but urged finalisation of a new contract "soon" due to worsening congestion problems at key West Coast ports in both the US and Canada.

"We ask that both parties recognise that time is of the essence. We encourage you to stay the course, complete the contract negotiations as soon as possible and work to resolve the current congestion issues without further interrupting the flow of commerce.

"We believe that a new agreement can be reached that will be fair to both parties and ensure the continued success and competitiveness of West Coast ports, your organisations and the stakeholders who rely on the timely and efficient movement of goods through the ports," they concluded.