By Laura Stevens 

A few retailers, including Eddie Bauer and Pacific Sunwear, are warning customers that their holiday packages are being delayed and blaming what they say are broader problems at FedEx Corp.

"FedEx is experiencing a backlog that is delaying standard shipments by several days or even weeks. All online merchants are affected, and not just PacSun," Pacific Sunwear wrote in an email Monday to customers. "Destinations in the northeast United States are being impacted the most."

A message on Eddie Bauer's customer service phone line Wednesday morning echoed the same concern.

FedEx said Wednesday it is running operations around the clock to "accommodate additional unforeseen volume from some customers," but that its delivery network is "performing as designed for the forecasted volumes from our major retail and e-tail customers."

"If customers shipped prior to the published deadlines, we plan to deliver the shipment by Christmas," a FedEx spokeswoman said.

Officials at Eddie Bauer LLC and Pacific Sunwear of California Inc. couldn't immediately be reached for comment.

Industry consultants who work with retailers said that the networks of both FedEx and rival United Parcel Service Inc. appeared to be at capacity this week, and the companies were enforcing volume limits on some retailers.

A UPS spokesman said Wednesday that the company's network is running 98% on time, and that it has been able to accommodate about 200 customers' requests for additional volume. "UPS has worked closely with customers to establish detailed operating plans to ensure available capacity and cut-off times are understood so there are no surprises for either party, " he added.

Last week, online retailer Jet.com became one of the first to tell customers its packages might not arrive before Christmas, although it didn't name which delivery companies might be responsible. Since then, a spokeswoman says nearly all of the packages have arrived in time.

Other retailers said their orders were shipping normally. "We don't see any indication that we are going to miss a significant number of Christmas packages this year," said a Wal-Mart Stores Inc. spokesman. "There is always a small amount of orders that might not get to customers, but so far looks like things are the same as last year."

Last week, FedEx executives said on an earnings call it was the company's busiest holiday season ever, and there was no sign it would let up. FedEx Chief Executive Fred Smith said some e-commerce shippers were doing better than others this holiday.

"The people that have the real problem in the e-commerce business by and large are those that view the transportation companies as some sort of utility or a vendor and they make some really, really bad decisions," Mr. Smith said. He didn't elaborate.

FedEx originally expected to deliver 317 million packages over the holidays, an increase of 12% over last year. It didn't provide an update last week. FedEx is delivering the smallest share of holiday shipments this season when compared with UPS and the U.S. Postal Service, which have forecast holiday volumes of 630 million and more than 600 million, respectively, including an additional week of deliveries.

A UPS spokesman said Wednesday the company "has worked closely with customers to establish detailed operating plans to ensure available capacity and cut-off times are understood, so there are no surprises for either party. UPS is efficiently using all available capacity in line with our detailed peak plans."

Susan Davis of Le Claire, Iowa, ordered a "Star Wars"-themed T-shirt from Kohl's Corp. on Nov. 28 that was supposed to have been delivered by FedEx within three to eight days. But by Dec. 20, the day Ms. Davis's family gathered to celebrate an early Christmas, the T-shirt still hadn't arrived. "We joked that The Force had it," said Ms. Davis, who owns a restaurant with her husband.

The T-shirt and another order Ms. Davis placed with Kohl's on Dec. 2 for a Mickey Mouse T-shirt, finally arrived on Wednesday, too late for the family gathering. Kohl's declined to comment on shipping issues.

Suzanne Kapner and Sarah Nassauer contributed to this article.

Write to Laura Stevens at laura.stevens@wsj.com

(END) Dow Jones Newswires

December 23, 2015 17:39 ET (22:39 GMT)

Copyright (c) 2015 Dow Jones & Company, Inc.