West Coast port operators and dock workers have not had a contract since June, and retailers are starting to worry about whether they will get their shipments in time for the holiday shopping rush.

That’s the gist of the letter Matt Shay, chief executive of the National Retail Federation in Washington, sent today to leaders on both sides of the bargaining table. Shay contends the lack of a contract for longshore workers is to blame for congestion at West Coast ports.

The trade group is asking both sides to reinstate the old contract through November as a means to avoid shipping disruptions before the holiday shopping season.

“Members are extremely concerned. This is the height of our shipping season,” said Jonathan Gold, the National Retail Federation’s vice president for supply chain and customs policy.

In labor talks, West Coast port operators are represented by the Pacific Maritime Association and dock workers are represented by the International Longshore and Warehouse Union.

Union spokesman Craig Merrilees said negotiators are trying to reach an agreement, but he was unimpressed by the National Retail Federation’s plea for workers to go back to the old deal.

“Who cares what the National Retail Federation thinks?,” he asked. “They’re anti-union, anti-worker. It’s Target and Walmart.”